Vehicle and braking feedback control method for the same

ABSTRACT

The present disclosure discloses a vehicle and a braking feedback control method for the same. The braking feedback control method includes the following steps: detecting a current speed of a vehicle and a depth of a braking pedal of the vehicle; when the current speed of the vehicle is greater than a preset speed, the depth of the braking pedal is greater than 0, and an anti-lock braking system of the vehicle is in a non-working state, controlling the vehicle to enter a braking feedback control mode, where when the vehicle is in the braking feedback control mode, a required braking torque corresponding to the vehicle is obtained according to the depth of the braking pedal, and a braking torque of a first motor generator, a braking torque of a second motor generator, and a braking torque of basic braking performed on the vehicle are distributed according to the required braking torque.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of InternationalApplication No. PCT/CN2014/089831, filed on Oct. 29, 2014, which isbased on and claims priority to and benefits of Chinese PatentApplication Serial No. 201410044602.7, filed with the State IntellectualProperty Office of P. R. China on Jan. 30, 2014. The entire contents ofthe above-referenced applications are incorporated herein by reference.

FIELD

The present disclosure relates to the technical field of vehicles, andmore particularly to a braking feedback control method for a vehicle anda vehicle.

BACKGROUND

Currently, in a braking process of an automobile, mechanical energy ismostly converted into thermal energy through the friction of a brake andthermal energy is then wasted. Although a method for controllingrecycling of braking energy of an electric automobile is disclosed inthe related art, only factors such as a power battery and a motorgenerator system are considered in the method, and a recyclable currentduring braking of an electric automobile is controlled according to atorque value fed back by a motor generator, to accomplish recycling ofbraking energy.

Moreover, most of the braking feedback control strategies in the relatedart are for parallel/series two-wheel drive hybrid vehicles, and aremainly classified into two types: a parallel control strategy and aseries control strategy. In the parallel control strategy, an originalfrictional braking force is not adjusted and a feedback braking force isadded to original friction braking to jointly implement a brakingfunction, so a recycling rate of braking energy is low and brakingexperience is poor. In the series control strategy, a frictional forceneeds to be adjusted, a recycling rate of braking energy is large, andbraking experience is also desirable; however, because a frictionalbraking force is difficult to adjust, a control process is relativelycomplex. Therefore, the braking feedback control strategies in therelated art need to be improved.

SUMMARY

The present disclosure seeks to solve at least one of the foregoingtechnical disadvantages.

A first objective of the present disclosure is to provide a brakingfeedback control method for a vehicle, so that energy can be properlydistributed between an engine unit and a motor generator during brakingof a vehicle, thus increasing braking feedback efficiency, and realizinghigh fuel economic efficiency, low discharge, and stable drivingperformance.

A second objective of the present disclosure is to provide a vehiclewith braking feedback control.

To achieve the foregoing objectives, an embodiment of a first aspect ofthe present disclosure provides a braking feedback control method for avehicle, where the vehicle includes an engine unit, a transmission unitadapted to selectively couple with the engine unit and also configuredto transmit the power generated by the engine unit, a first motorgenerator coupled with the transmission unit, an output unit, a powerswitching device, a second motor generator configured to drive at leastone of front and rear wheels of the vehicle, and a power battery forsupplying power to the first motor generator and the second motorgenerator, where the output unit is configured to transmit the powertransmitted by the transmission unit to at least one of the front andrear wheels of the vehicle, and the power switching device is adapted toenable or interrupt power transmission between the transmission unit andthe output unit. The braking feedback control method includes thefollowing steps: detecting the current speed of the vehicle and thedepth of a braking pedal of the vehicle; when the current speed of thevehicle is greater than a preset speed, the depth of the braking pedalis greater than 0, and an anti-lock braking system of the vehicle is ina non-working state, controlling the vehicle to enter a braking feedbackcontrol mode, where when the vehicle is in the braking feedback controlmode, a required braking torque corresponding to the vehicle is obtainedaccording to the depth of the braking pedal, and a braking torque of thefirst motor generator, a braking torque of the second motor generator,and a braking torque of basic braking performed on the vehicle aredistributed according to the required braking torque.

For the braking feedback control method for a vehicle according toembodiments of the present disclosure, when the vehicle performs brakingfeedback, a required braking torque corresponding to the vehicle isobtained according to the depth of a braking pedal, and a braking torqueof a first motor generator, a braking torque of a second motorgenerator, and a braking torque of basic braking performed on thevehicle are properly distributed according to the required brakingtorque, which fully considers energy feedback efficiency, brakingsafety, and driving comfort during braking of the vehicle, so high fueleconomic efficiency, low discharge, and stable driving performance canbe realized, thus maximizing the mileage, the ride comfort, and thesteering capability of the vehicle. Meanwhile, in some embodiments ofthe present disclosure, power output by the engine unit and/or a firstmotor generator may be output to an output unit via a power switchingdevice, and the output unit then outputs the power to at least one offront and rear wheels of the vehicle. Further, because of the provisionof a second motor generator, the second motor generator may performtorque compensation on at least one of the front and rear wheels, andmay also cooperate with the engine unit and the first motor generator todrive the vehicle, thus increasing the number of operation modes of thevehicle, so that the vehicle may be better adapted to differentoperating conditions, thus achieving better fuel economic efficiencywhile reducing the emission of harmful gases. In addition, the method issimple and reliable and is easy to implement.

To achieve the foregoing objectives, an embodiment of a second aspect ofthe present disclosure provides a vehicle, including: an engine unit; atransmission unit, where the transmission unit is adapted to selectivelycouple with the engine unit and also configured to transmit the powergenerated by the engine unit; a first motor generator, where the firstmotor generator is coupled with the transmission unit; an output unit,where the output unit is configured to transmit the power transmitted bythe transmission unit to at least one of the front and rear wheels ofthe vehicle; a power switching device, where the power switching deviceis adapted to enable or interrupt power transmission between thetransmission unit and the output unit; a second motor generator, wherethe second motor generator is configured to drive at least one of thefront and rear wheels; a power battery, where the power battery isrespectively connected to the first motor generator and the second motorgenerator to supply power to the first motor generator and the secondmotor generator; and a controller, where when the current speed of thevehicle is greater than a preset speed, the depth of the braking pedalof the vehicle is greater than 0, and an anti-lock braking system of thevehicle is in a non-working state, the controller controls the vehicleto enter a braking feedback control mode, where when the vehicle is inthe braking feedback control mode, the controller obtains a requiredbraking torque corresponding to the vehicle according to the depth ofthe braking pedal, and distributes a braking torque of the first motorgenerator, a braking torque of the second motor generator, and a brakingtorque of basic braking performed on the vehicle according to therequired braking torque.

For the vehicle according to embodiments of the present disclosure,during braking feedback, a required braking torque corresponding to thevehicle can be obtained according to the depth of the braking pedal, anda braking torque of a first motor generator, a braking torque of asecond motor generator, and a braking torque of basic braking performedon the vehicle can be properly distributed according to the requiredbraking torque, which fully considers the energy feedback efficiency,the braking safety, and the driving comfort during braking of thevehicle, so high fuel economic efficiency, low discharge, and stabledriving performance can be realized, thus maximizing the mileage, theride comfort, and steering capability. Meanwhile, in some embodiments ofthe present disclosure, power output by the engine unit and/or a firstmotor generator may be output to an output unit via a power switchingdevice, and the output unit then outputs the power to at least one offront and rear wheels of the vehicle. Further, because of the provisionof a second motor generator, the second motor generator may performtorque compensation on at least one of the front and rear wheels, andmay also cooperate with the engine unit and the first motor generator todrive the vehicle, thus increasing the number of operation modes of thevehicle, so that the vehicle may be better adapted to differentoperating conditions, thus achieving better fuel economic efficiencywhile reducing the emission of harmful gases.

Additional aspects and advantages of the present disclosure will begiven in part in the following descriptions, become apparent in partfrom the following descriptions, or be learned from the practice of thepresent disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other aspects and advantages of the present disclosurewill become apparent and more readily appreciated from the followingdescriptions of the embodiments made with reference to the drawings, inwhich:

FIG. 1 is a principle diagram of a power transmission system accordingto an embodiment of the present disclosure;

FIG. 2 is a schematic view of a power transmission system according toan embodiment of the present disclosure;

FIG. 3 is a schematic view of a power transmission system according toanother embodiment of the present disclosure;

FIG. 4 is a schematic view of a power transmission system according tostill another embodiment of the present disclosure;

FIG. 5 is a schematic view of a power transmission system according toyet another embodiment of the present disclosure;

FIG. 6 is a schematic view of a power transmission system according toyet another embodiment of the present disclosure;

FIG. 7 is a schematic view of a power transmission system according toyet another embodiment of the present disclosure;

FIG. 8 is a schematic view of a power transmission system according toyet another embodiment of the present disclosure;

FIG. 9 is a schematic view of a power transmission system according toyet another embodiment of the present disclosure;

FIG. 10 is a schematic view of a power transmission system according toyet another embodiment of the present disclosure;

FIG. 11 is a schematic view of a power transmission system according toyet another embodiment of the present disclosure;

FIG. 12 is a schematic view of a power transmission system according toyet another embodiment of the present disclosure;

FIG. 13 is a schematic view of a power transmission system according toyet another embodiment of the present disclosure;

FIG. 14 is a schematic view of a power transmission system according toyet another embodiment of the present disclosure;

FIG. 15 is a schematic view of a power transmission system according toyet another embodiment of the present disclosure;

FIG. 16 is a schematic view of a power transmission system according toyet another embodiment of the present disclosure;

FIG. 17 is a schematic view of a power transmission system according toyet another embodiment of the present disclosure;

FIG. 18 is a schematic view of a power transmission system according toyet another embodiment of the present disclosure;

FIG. 19 is a schematic view of a power transmission system according toyet another embodiment of the present disclosure;

FIG. 20 is a flowchart of a braking feedback control method for avehicle according to an embodiment of the present disclosure;

FIG. 21 is a schematic view of an energy transfer path of a powertransmission system of a vehicle according to an embodiment of thepresent disclosure;

FIG. 22 is a diagram of information interaction of braking feedbackcontrol of a vehicle according to an embodiment of the presentdisclosure;

FIG. 23 is a flowchart of a vehicle entering a braking feedback controlmode according to an embodiment of the present disclosure;

FIG. 24 is a detailed flowchart of braking feedback control of a vehicleaccording to an embodiment of the present disclosure;

FIG. 25 is a flowchart of electrical braking torque distribution duringbraking feedback control of a vehicle according to an embodiment of thepresent disclosure; and

FIG. 26 is a schematic view of a vehicle according to an embodiment ofthe present disclosure.

DETAILED DESCRIPTION

Reference will be made in detail to embodiments of the presentdisclosure. The embodiments described herein with reference to drawingsare explanatory, illustrative, and should be used to generallyunderstand the present disclosure. The embodiments shall not beconstrued to limit the present disclosure. The same or similar elementsand the elements having same or similar functions are denoted by likereference numerals throughout the descriptions.

The disclosure below provides many different embodiments or examples toimplement different structures of the present disclosure. To simplifythe disclosure of the present disclosure, the components and settings inthe specific examples below are described. These are merely examples,and the objective is not to limit the present disclosure. In addition,in the present disclosure, reference numerals and/or letters may berepeated in different examples. Such repetition is for the purpose ofsimplification and clarity, but the repeated numerals and/or letters donot indicate relationships between discussed various embodiments and/orsettings. In addition, the present disclosure provides examples ofvarious specific processes and materials, but a person of ordinary skillin the art may realize applicability of another process and/or use ofanother material. In addition, the structure in which the first featureis “on” the second feature described below may include an embodiment inwhich the first and second features are form directly contacting eachother, or may include an embodiment in which an additional feature isformed between the first and second features, so that the first andsecond features may not contact directly.

In the description of the present disclosure, it should be understoodthat, unless specified or limited otherwise, the terms “mounted,”“connected,” and “coupled” and variations thereof are used broadly andencompass such as mechanical or electrical mountings, connections andcouplings, also can be inner mountings, connections and couplings of twocomponents, and further can be direct mountings, connections, andcouplings and indirect mountings, connections, and couplings by using anintermediate medium, and the specific meanings of the foregoing termscan be understood by those skilled in the art according to the specificcases.

Referring to the descriptions below and the accompanying drawings, theseand other aspects of embodiments of the present disclosure will becomeclear. In these descriptions and the accompanying drawings, somespecific implementation manners in some embodiments of the presentdisclosure are specifically disclosed, to represent some manners ofimplementing the principles of embodiments of the present disclosure.However, it would be appreciated that the scope of embodiments of thepresent disclosure is not limited to this. In contrast, embodiments ofthe present disclosure include all changes, modifications, andequivalents that fall within the spirit and scope of the appendedclaims.

Before the vehicle and the braking feedback braking method for the sameaccording to embodiments of the present disclosure are described below,a braking feedback control strategy for an electric automobile in therelated art is described first.

The braking feedback control strategy refers to that during decelerationor braking of an electric automobile, a motor controller performsfeedback control according to a formulated strategy, charges a powerbattery, and increases the mileage of an electric automobile, thusreducing the discharge of pollutants and the wear caused by mechanicalbraking, and at the same time optimize the ride comfort of the electricautomobile. Therefore, to reduce energy consumption of an electricautomobile, mitigate energy crisis and environmental pressure, in-depthresearch needs to be performed on braking feedback control strategiesfor electric automobiles.

The inventor of this application finds during research that most of thebraking feedback control strategies in the related art are forparallel/series two-wheel drive hybrid vehicles, and are mainlyclassified into two types: a parallel control strategy and a seriescontrol strategy. In the parallel control strategy, an originalfrictional braking force is not adjusted and a feedback braking force isadded to original friction braking to jointly implement a brakingfunction, so a recycling rate of braking energy is low and brakingexperience is poor. In the series control strategy, a frictional forceneeds to be adjusted, a recycling rate of braking energy is large, andbraking experience is also desirable; however, because a frictionalbraking force is difficult to adjust, a control process is relativelycomplex.

For a feedback torque curve (that is, a braking pedal depth-brakingfeedback torque curve is obtained through calculation according to abasic braking pedal travel-deceleration curve) defined in a brakingfeedback control strategy of a vehicle, factors such as the brakingfeedback efficiency of the vehicle, the ride comfort of the vehicle, andthe handling stability and the operating mode further need to be fullyconsidered, so as to seek an optimal balance curve between the economicefficiency and the ride comfort. In addition, in consideration of that avehicle may be braked in different modes (for example, emergent braking,normal braking, and braking on a long downhill slope), influence ofcharacteristics of a motor generator, the slope of a road, pedal depth,and the like on braking feedback requirements and feedback influence ofbraking energy further need to be considered.

In view of the foregoing deficiencies in the related art, embodiments ofthe present disclosure provide a vehicle and a braking feedback controlmethod for the same, so that during braking feedback control of avehicle, factors (such as the economic efficiency, the ride comfort, andworking states of other related modules) are fully considered, and incombination with the analysis of characteristics of different roadconditions, a relatively complete braking energy feedback curve andcontrol strategy are formulated, thus maximizing the mileage, the ridecomfort, and the steering capability of the vehicle.

The vehicle and the braking feedback control method for the sameaccording to the present disclosure are described below with referenceto the accompanying drawings.

A power transmission system 100 according to embodiments of the presentdisclosure will be described in detail below with reference to FIGS.1-19. The power transmission system 100 is applicable to a vehicle, suchas a hybrid vehicle with an engine unit 1 and a motor generator.

As shown in the figures, the power transmission system 100 according toembodiments of the present disclosure may include an engine unit 1, atransmission unit 2 a, a first motor generator 41, a second motorgenerator 42, an output unit 5, and a power switching device (e.g., asynchronizer 6, and a clutch 9).

The transmission unit 2 a is adapted to be selectively coupled with theengine unit 1. The engine unit 1 may selectively output a powergenerated by the engine unit 1 to the transmission unit 2 a via theclutch 9 or the like. Alternatively, the transmission unit 2 a may alsooutput, for example, a starting torque from the first motor generator 41to the engine unit 1, so as to start the engine unit 1. In the contextof the present disclosure, the phrase “the transmission unit 2 a iscoupled with the engine unit 1” means that the power can be transferredbetween the engine unit 1 and the transmission unit 2 a directly or viaother components, and the coupling between the transmission unit 2 a andthe engine unit 1 is also referred to as a power coupling.

The engine unit 1 generates energy by mixing liquid or gaseous fuel andair and then combusting the mixed fuel and air therein, and the energyis converted into mechanical energy. The engine unit 1 of the vehiclemay generally adopt a four-stroke gasoline or diesel engine. The engineunit 1 may generally include a block, a crank-connecting rod mechanism,a valve mechanism, a supply system, an ignition system, a coolingsystem, a lubrication system and the like.

The block is an assembled body of individual mechanisms and systems ofthe engine unit 1. The crank-connecting rod mechanism may convert thelinear reciprocating motion of a piston into the rotary motion of acrankshaft, and output a drive force. The valve mechanism is configuredto charge or discharge a gas at a predetermined time, so as to ensurethe smooth performing of each cycle of the engine unit 1. The supplysystem may supply a mixture of oil and gas to a cylinder for combustion.The cooling system is configured to cool the engine unit 1, so as toensure that the operating temperature of the engine unit 1 is within asuitable temperature range. The lubrication system is configured tolubricate individual motion pairs in the engine unit 1, so as to reducethe wear and energy loss.

It would be appreciated that the foregoing engine unit 1 as well asspecific structures and operation principles of individual sub-systemsand sub-mechanisms of the engine unit 1 are well known to those skilledin the art, so the detailed description thereof will be omitted here forclarity purpose.

The first motor generator 41 is coupled with the transmission unit 2 a.In other words, the first motor generator 41 cooperates with thetransmission unit 2 a to transmit the power. That is, the first motorgenerator 41 may drive the transmission unit 2 a, while the transmissionunit 2 a may drive the first motor generator 41.

For example, the engine unit 1 may output at least a part of the powergenerated to the first motor generator 41 via the transmission unit 2 a,and the first motor generator 41 may generate electricity and convertmechanical energy into electric energy to be stored in an energy storagecomponent such as a battery component. As another example, the firstmotor generator 41 may convert electric energy from the batterycomponent into mechanical energy, and output the mechanical energy tothe output unit 5 via the transmission unit 2 a to drive the vehicle.

The first motor generator 41 is a motor having functions of both a motorand a generator. As used in the present disclosure, the term “motorgenerator” refers to a motor having functions of both a motor and agenerator, unless specified otherwise.

The output unit 5 is configured to transmit a power transmitted by thetransmission unit 2 a to wheels 200 (e.g., one of front and rear wheels210 and 220) of the vehicle. The output unit 5 is adapted to output thepower from the transmission unit 2 a.

The power switching device such as the synchronizer 6 is adapted toenable or interrupt a power transmitting between the output unit 5 andthe transmission unit 2 a. In other words, the power switching devicemay output the power output from the transmission unit 2 a to at leastone of front and rear wheels 210, 220 via the output unit 5, or thepower switching device may also disconnect the transmission unit 2 afrom the output unit 5 and the transmission unit 2 a may not output thepower to the front and/or rear wheels 210, 220 via the output unit 5directly.

As shown in FIGS. 1-13, the second motor generator 42 is configured todrive the front and/or rear wheels 210, 220.

Therefore, when the output unit 5 is configured to drive the frontwheels 210 and the second motor generator 42 is also configured to drivethe front wheels 210, the vehicle having the power transmission system100 may be operable as a two-wheel drive vehicle. When the output unit 5is configured to drive the front wheels 210 and the second motorgenerator 42 is configured to drive the rear wheels 220, the vehiclehaving the power transmission system 100 may be operable as a four-wheeldrive vehicle, and may switch between a two-wheel drive mode and afour-wheel drive mode. When the output unit 5 is configured to drive thefront wheels 210 and the rear wheels 220 and the second motor generator42 is configured to drive the front wheels 210 or the rear wheels 220,the vehicle having the power transmission system 100 may be operable asa four-wheel drive vehicle.

With the power transmission system 100 according to embodiments of thepresent disclosure, the power output by at least one of the engine unit1 and the first motor generator 41 may be output to the output unit 5via the power switching device, and then output by the output unit 5 tothe front and/or rear wheels 210, 220 of the vehicle.

Meanwhile, because of the provision of the second motor generator 42,the second motor generator 42 may compensate for the torque of the frontwheels 210 or the rear wheels 220, and may also cooperate with theengine unit 1 and the first motor generator 41 to drive the vehicle,thus increasing the number of operation modes of the vehicle. Therefore,the vehicle may be adapted to different operating conditions, thusachieving better fuel economic efficiency while reducing the emission ofharmful gases.

In some embodiments of the present disclosure, as shown in FIGS. 1-16,the power switching device is configured as a synchronizer 6, and thesynchronizer 6 is adapted to selectively synchronize between the outputunit 5 and the transmission unit 2 a, so as to output the power via theoutput unit 5 to drive the wheels 200 of the vehicle.

The function of the synchronizer 6 may be to eventually synchronize theoutput unit 5 and the transmission unit 2 a, i.e., under the action ofthe synchronizer 6, the output unit 5 and the transmission unit 2 a mayoperate synchronously, such that the power from the transmission unit 2a may be output with the output unit 5 as a power output terminal.However, when the transmission unit 2 a and the output unit 5 are notsynchronized by the synchronizer 6, the power from the transmission unit2 a may not be output to the wheels 200 via the output unit 5 directly.

The synchronizer 6 functions to switch the power. That is, when thesynchronizer 6 is in an engaged state, the power from the transmissionunit 2 a may be output via the output unit 5 to drive the wheels 200;and when the synchronizer 6 is in a disengaged state, the transmissionunit 2 a may not transmit the power to the wheels 200 via the outputunit 5. In this way, by controlling the synchronizer 6 to switch betweenthe engaged state and the disengaged state, the switching of the drivemode of the vehicle may be realized.

Because of special application scenarios, the synchronizer 6 has thefollowing advantages.

a. When the synchronizer 6 is in a disengaged state, the powertransmitting between the engine unit 1, the transmission unit 2 a, thefirst motor generator 41 and the wheels 200 can be severed, such thatoperations such as electricity generation, driving, and power/torquetransmission may not influence each other, which is very important inreducing the energy consumption of the vehicle. The synchronizer 6 maymeet this requirement well, while incomplete separation of frictionplates usually occurs in the clutch, thus increasing the friction lossand energy consumption.

b. When the synchronizer 6 is in an engaged state, the synthesized(coupled) driving force of the engine unit 1 and the first motorgenerator 41 can be transferred to the wheels 200 after the torquemultiplication of the transmission unit 2 a, or the driving force of thewheels 200 can be transferred to the first motor generator 41 togenerate electricity, both of which require that the power couplingdevice transmit a large torque and have high stability. The synchronizer6 may meet this requirement well. However, if a clutch is used, anoversize clutch which does not match with the entire system (includingan engine, a transmission, a motor, etc.) needs to be designed, thusincreasing the arrangement difficulty, the weight and the cost, andhaving the risk of slipping under the action of an impact torque.

Moreover, the first motor generator 41 may adjust the speed of thetransmission unit 2 a, for example, the first motor generator 41 mayadjust the speed of the transmission unit 2 a with the rotating speed ofthe output unit 5 as a target value, so as to match the speed of thetransmission unit 2 a with the speed of the output unit 5 in a timeefficient manner, thus reducing the time required by the synchronizationof the synchronizer 6 and reducing the energy loss. Meanwhile, no torqueengagement of the synchronizer 6 may be achieved, thus greatly improvingthe transmission efficiency, synchronization controllability andreal-time synchronization of the vehicle. In addition, the life of thesynchronizer 6 may be further extended, thus reducing the maintenancecost of the vehicle. Furthermore, the power transmission system 100according to embodiments of the present disclosure is compact instructure and easy to control.

In some embodiments of the present disclosure, as shown in FIGS. 2-7,the transmission unit 2 a includes a transmission power input part 21 aand a transmission power output part 22 a. The transmission power inputpart 21 a is selectively engaged with the engine unit 1 to transmit thepower generated by the engine unit 1. The transmission power output part22 a is configured to output the power from the transmission power inputpart 21 a to the output unit 5 via the synchronizer 6.

As shown in FIGS. 2-7, the transmission power input part 21 a furtherincludes an input shaft (e.g., a first input shaft 21, a second inputshaft 22) and a driving gear 25 mounted on the input shaft. The inputshaft is selectively engaged with the engine unit 1 to transmit thepower generated by the engine unit 1. In other words, when the engineunit 1 needs to output the power to the input shaft, the engine unit 1may be engaged with the input shaft, such that the power output by theengine unit 1 may be transferred to the input shaft. The engagementbetween the engine unit 1 and the input shaft may be achieved by meansof a clutch (e.g., a dual clutch 31), which will be described in detailbelow, and is no longer elaborated herein.

As shown in FIGS. 2-7, the transmission power output part 22 a includesan output shaft 24, and a driven gear 26 mounted on the output shaft 24and configured to mesh with the driving gear 25 on the input shaft.

As shown in FIGS. 2-5, the output shaft 24 is configured to output atleast a part of the power transmitted by the input shaft. The outputshaft 24 and the input shaft cooperate with each other to transmit thepower. For example, preferably, the power transmission between theoutput shaft 24 and the input shaft may be realized by means of thedriving gear 25 and the driven gear 26.

It would be appreciated that the power transmission between the outputshaft 24 and the input shaft is not limited to this. For example, thepower transmission between the output shaft 24 and the input shaft mayalso be realized by means of a belt transmission mechanism, a rack andpinion transmission mechanism or the like. For example, a suitablestructure and manner of may be specifically selected according topractical applications by a person skilled in the art.

The output shaft 24 is configured to transmit at least a part of thepower on the input shaft. For example, when the power transmissionsystem 100 is in a certain transmission mode where for example, thefirst motor generator 41 generates electricity, a part of the power onthe input shaft may be used for the electricity generating of the firstmotor generator 41, and the other part of the power on the input shaftmay be used to drive the vehicle to run. All power on the input shaftmay be used for the electricity generation of the first motor generator41.

In some embodiments of the present disclosure, the power transmittingbetween the first motor generator 41 and one of the input shaft and theoutput shaft 24 may be direct or indirect. As used herein, the term“direct power transmission” means that the first motor generator 41 isdirectly coupled with a corresponding one of the input shaft and theoutput shaft 24 for power transmission, without using any intermediatetransmission components such as a speed changing device, a clutchdevice, or a transmission device. For example, an output terminal of thefirst motor generator 41 can be directly and rigidly connected with oneof the input shaft and the output shaft 24. The direct powertransmission has the advantages of eliminating the intermediatetransmission components and reducing the energy loss during the powertransmission.

As used herein, the term “indirect power transmission” refers to anyother power transmission manners other than the direct powertransmission, for example, the power transmission by means ofintermediate transmission components such as a speed changing device, aclutch device, or a transmission device. The indirect power transmissionhas the advantages of enabling convenient arrangement and achieving thedesired transmission ratio by providing a speed changing device and thelike.

The output unit 5 may be used as a power output terminal of the outputshaft 24 for outputting the power on the output shaft 24. The outputunit 5 and the output shaft 24 may rotate differentially and notsynchronously. In other words, there can be a rotating speed differencebetween the output unit 5 and the output shaft 24, and the output unit 5and the output shaft 24 are not rigidly fixed with each other.

The synchronizer 6 is disposed on the output shaft 24. As shown in FIGS.1-6, the synchronizer 6 may include a splined hub 61 and a synchronizingsleeve 62. The splined hub 61 may be fixed on the output shaft 24 suchthat the splined hub 61 can rotate synchronously with the output shaft24, while the synchronizing sleeve 62 may move in an axial direction ofthe output shaft 24 relative to the splined hub 61 so as to selectivelyengage with the output unit 5, such that the output unit 5 can rotatesynchronously with the output shaft 24. In this way, the power may betransferred from the output unit 5 to the front and/or rear wheels 210,220, thus driving the wheels 200. However, it would be appreciated thatthe structure of the synchronizer 6 is not limited to this.

With the power transmission system 100 according to embodiments of thepresent disclosure, the power output by at least one of the engine unit1 and the first motor generator 41 may be output from the output unit 5by the engagement of the synchronizer 6, such that the powertransmission system 100 is compact in structure and easy to control.Moreover, during the switching of the operating modes of the vehicle, itis possible for the synchronizer 6 to switch from a disengaged state toan engaged state, and the first motor generator 41 may adjust therotating speed of the output shaft 24 with the rotating speed of theoutput unit 5 as a target value, so as to match the rotating speed ofthe output shaft 24 with the rotating speed of the output unit 5 in ashort time, thus facilitating the engagement of the synchronizer 6,greatly improving the transmission efficiency and reducing the energyloss, and realizing no torque engagement of the synchronizer 6.Furthermore, the radial frictional force is much smaller than theaverage value in the related art or even there is no radial frictionalforce during the engagement of the synchronizer 6.

In some embodiments of the present disclosure, the output unit 5 isconfigured to drive a first pair of wheels of the vehicle, and there isa pair of second motor generators 42 configured to drive the first pairof wheels. Further, there may be a plurality of second motor generators.For example, the power transmission system 100 further includes a thirdmotor generator 43 configured to drive a second pair of wheels of thevehicle. For example, as shown in FIGS. 2-8, the first pair of wheelsrefers to the front wheels 210 of the vehicle, and the second pair ofwheels refers to the rear wheels 220 of the vehicle. It is understoodthat in other embodiments, the first pair of wheels can refer to therear wheels 220 and the second pair of wheels can refer to the frontwheels 210.

Therefore, the power transmission system 100 according to embodiments ofthe present disclosure has four types of power output sources, i.e. theengine unit 1, the first motor generator 41, the second motor generator42 and the third motor generator 43, in which the engine unit 1, thefirst motor generator 41 and the second motor generator 42 may beconfigured to drive one pair of wheels of the vehicle, and the thirdmotor generator 43 may be configured to drive the other pair of wheelsof the vehicle. Therefore, the vehicle having the power transmissionsystem 100 is operable as a four-wheel drive vehicle.

Moreover, during the switching of operating modes of the vehicle, it ispossible for the synchronizer 6 to switch from the disengaged state tothe engaged state, and the first motor generator 41 may adjust therotating speed of the output shaft 24 with the rotating speed of theoutput unit 5 as a target value, so as to match the rotating speed ofthe output shaft 24 with the rotating speed of the output unit 5 in ashort time, thus facilitating the engagement of the synchronizer 6,greatly improving the transmission efficiency and reducing the energyloss.

Meanwhile, by the provision of the second motor generator 42 and thethird motor generator 43, the second motor generator 42 and the thirdmotor generator 43 may compensate for the torque of the wheels 200,which is indirectly reflected in the output of the output unit 5. Thatis, the second motor generator 42 and the third motor generator 43 mayindirectly adjust the rotating speed of the output unit 5. For example,when the synchronizer 6 switches from the disengaged state to theengaged state, the second motor generator 42 and the third motorgenerator 43 may indirectly adjust the rotating speed of the output unit5 according to requirements, so as to match the rotating speed of theoutput shaft 24 with the rotating speed of the output unit 5 in a shorttime, thus facilitating the engagement of the synchronizer 6.

Furthermore, the second motor generator 42 and the third motor generator43 may cooperate with the first motor generator 41 to adjust therotating speed of the output unit 5 simultaneously, so as to synchronizethe rotating speed of the output shaft 24 and the rotating speed of theoutput unit 5 in a shorter time, thus facilitating the engagement of thesynchronizer 6 and greatly improving the transmission efficiency.

Optionally, the first motor generator 41 may adjust the rotating speedof the output unit 5 separately. Alternatively, optionally, at least oneof the second motor generator 42 and the third motor generator 43 mayadjust the rotating speed of the output unit 5 separately. Furthermore,optionally, the first motor generator 41, the second motor generator 42and the third motor generator 43 may adjust the rotating speed of theoutput unit 5 simultaneously.

In this way, the output of the power from the transmission unit 2 a maybe controlled by the engagement/disengagement of the synchronizer 6, andwhen the synchronizer 6 switches from the disengaged state to theengaged state, at least one of the first motor generator 41, the secondmotor generator 42 and the third motor generator 43 may compensate forthe speeds of the output shaft 24 and the output unit 5, so as to matchthe rotating speed of the output shaft 24 with the rotating speed of theoutput unit 5 rapidly, thus realizing no torque engagement of thesynchronizer 6 rapidly.

In some embodiments of the present disclosure, as shown in FIGS. 2-9,there is a plurality of the input shafts, i.e. two or more input shafts.The input shafts are coaxially nested sequentially. For example, ifthere are N input shafts, the K^(th) input shaft is fitted over the(K−1)^(th) input shaft, where N≧K≧2, and central axes of the N inputshafts coincide with each other.

For example, as shown in FIGS. 2-7 and 9-19, when there are two inputshafts, e.g. the first input shaft 21 and the second input shaft 22, thesecond input shaft 22 is fitted over the first input shaft 21 andcentral axes of the two input shafts coincide with each other. Asanother example, as shown in FIG. 8, when there are three input shafts,e.g. the first input shaft 21, the second input shaft 22 and a thirdinput shaft 23, the third input shaft 23 is fitted over the second inputshaft 22, the second input shaft 22 is fitted over the first input shaft21, and central axes of the three input shafts coincide with each other.

When the engine unit 1 transmits the power to the input shaft or iscoupled with the input shaft for power transmitting, the engine unit 1may be selectively engaged with one of the input shafts. In other words,when the power from the engine unit 1 needs to be output, the outputterminal of the engine unit 1 may be engaged with one of the inputshafts, so as to rotate synchronously with the one of the input shafts.When the engine unit 1 does not need to operate or the engine unit 1 isidle, the engine unit 1 may be disconnected from individual input shaftsrespectively, i.e. the engine unit 1 is not coupled with any inputshaft, so as to interrupt the power transmission between the engine unit1 and individual input shafts.

Further, as shown in FIG. 2-6, one driving gear 25 is fixed on eachinput shaft, and the driving gear 25 rotates synchronously with theinput shaft. The fixing between the driving gear 25 and thecorresponding input shaft is not limited here, for example, the drivinggear 25 and the corresponding input shaft may be fixed by, for example,key fit or hot pressing, or may be formed integrally, as long as thesynchronous rotation of the driving gear 25 and the corresponding inputshaft is ensured.

A plurality of driven gears 26 is fixed on the output shaft 24, and thedriven gears 26 rotate synchronously with the output shaft 24. By way ofexample and without limitation, the fixing between the driven gear 26and the output shaft 24 may be realized by key fit or hot pressing, ormay be formed integrally.

However, the present disclosure is not limited to this. For example, thenumber of the driving gears 25 on each input shaft is not limited toone, and accordingly a plurality of driven gears 26 is fixed on theoutput shaft 24 to form a plurality of gears, which is implementable toa person skilled in the art.

As shown in FIG. 2-6, the driven gears 26 are configured to mesh withthe driving gears 25 on the input shafts respectively. In one embodimentof the present disclosure, the number of the driven gears 26 may be thesame as that of the input shafts. For example, when there are two drivengears 26, there are two input shafts, such that the two driven gears 26may be configured to mesh with the driving gears 25 on the two inputshafts to transmit the power, so as to make the two pairs of gears formtwo gears for power transmitting.

In an embodiment of the present disclosure, three or more input shaftsmay be provided according to the power transmitting requirements, andeach input shaft may be provided with one driving gear 25. Therefore,the larger the number of the input shafts, the larger the number of thegears is, and the wider range of the transmission ratio of the powertransmission system 100 is, so as to adapt to the power transmittingrequirements of various vehicles.

In some specific embodiments of the present disclosure, as shown inFIGS. 2-7, the input shafts include the first input shaft 21 and thesecond input shaft 22. The second input shaft 22 is fitted over thefirst input shaft 21. The second input shaft 22 is a hollow shaft, andthe first input shaft 21 is preferably a solid shaft. Alternatively, thefirst input shaft 21 may also be a hollow shaft.

The first input shaft 21 may be supported by bearings. For example, aplurality of bearings can be preferably disposed in an axial directionof the first input shaft 21 at a position not influencing the assemblyof other components. Similarly, the second input shaft 22 may also besupported by bearings.

Further, as shown in FIGS. 2-7, a dual clutch 31 is disposed between theengine unit 1 and the first and second input shafts 21, 22. The dualclutch 31 may be a dry dual clutch 31 or a wet dual clutch 31.

The dual clutch 31 has an input terminal 313, a first output terminal311 and a second output terminal 312. The engine unit 1 is connected tothe input terminal 313 of the dual clutch 31. The engine unit 1 may beconnected to the input terminal 313 of the dual clutch 31 via forexample, a flywheel, a damper, or a torsion plate.

The first output terminal 311 of the dual clutch 31 is connected to androtates synchronously with the first input shaft 21. The second outputterminal 312 of the dual clutch 31 is connected to and rotatessynchronously with the second input shaft 22.

The input terminal 313 of the dual clutch 31 may be a shell of the dualclutch 31, and the first output terminal 311 and the second outputterminal 312 of the dual clutch 31 may be two driven discs. Generally,the shell may be disconnected from the two driven discs, such that theinput terminal 313 is disconnected from the first output terminal 311and the second output terminal 312. When one driven disc needs to beengaged, the shell can be controlled to engage with the correspondingdriven disc to rotate synchronously with the driven disc, e.g. the inputterminal 313 is engaged with one of the first output terminal 311 andthe second output terminal 312, such that the power transmitted from theinput terminal 313 may be output via one of the first output terminal311 and the second output terminal 312. Generally, the shell is engagedwith one driven disc at a time.

It would be appreciated that the specific engagement of the dual clutch31 is influenced by a control strategy. For a person skilled in the art,the control strategy may be adaptively set according to the desiredpower transmission mode, e.g. switching between a mode in which theinput terminal 313 is disconnected from the first output terminal 311and the second output terminal 312 and a mode in which the inputterminal 313 is engaged with one of the first output terminal 311 andthe second output terminal 312.

For example, as shown in FIGS. 2-7, since the input shaft has aconcentric dual-shaft structure and each input shaft is provided withonly one driving gear 25, the transmission unit 2 a has two differentgears, and the engine unit 1 may output the power to the output unit 5via the two gears, while the synchronizer 6 is always in an engagedstate to engage the output shaft 24 with the output unit 5.

During the gear shift, unlike the synchronizer in the related art, thesynchronizer 6 does not need to be first disengaged and then moveaxially to engage with other gears. Only the engagement/disengagement ofthe dual clutch 31 needs to be controlled, while the synchronizer 6 canremain in the engaged state. In this way, when the engine unit 1 outputsthe power to the output unit 5, only one gear shift actuating component,e.g. the dual clutch 31, needs to be controlled, while the synchronizer6 does not need to be controlled, thus simplifying the control strategygreatly, reducing the number of engagement/disengagement times of, e.g.synchronizer 6, and extending the life of the synchronizer 6.

In some embodiments of the present disclosure, the first motor generator41 is configured to cooperate with one of the driving gear 25 and thedriven gear 26 for power transmission. In other words, indirect powertransmission between the first motor generator 41 and one of the inputshaft and the output shaft 24 is performed.

Further, as an optional solution, an intermediate transmission mechanismmay be disposed between the first motor generator 41 and thecorresponding gear, and by way of example and without limitation, theintermediate transmission mechanism may be a worm and worm geartransmission mechanism, a one-stage or multi-stage gear pairtransmission mechanism, or a chain wheel transmission mechanism, or maybe a combination of the above transmission mechanisms in the case of noconflicting. In this way, the first motor generator 41 may be providedin different locations as needed, thus reducing the arrangementdifficulty of the first motor generator 41.

In order to facilitate the spatial arrangement, in an embodiment of thepresent disclosure, the first motor generator 41 may transmit the powervia an intermediate gear 411. For example, as shown in FIG. 3 (withreference to FIG. 2), indirect power transmission between the firstmotor generator 41 and the driving gear 25 on the first input shaft 21via the intermediate gear 411 can be performed. As another example, asshown in FIG. 2, indirect power transmission between the first motorgenerator 41 and the driving gear 25 on the second input shaft 22 viathe intermediate gear 411 can be performed

However, the present disclosure is not limited to this. In anotherembodiment of disclosure, the first motor generator 41 may be configuredto connect with one of the first input shaft 21 and the output shaft 24.For example, the first motor generator 41 may be configured to directlyconnect with the first input shaft 21. As another example, the firstmotor generator 41 may be configured to directly connect with the outputshaft 24. Direct connection between the first motor generator 41 and thecorresponding shaft may make the structure of the power transmissionsystem 100 more compact, and decrease the circumferential dimension ofthe power transmission system 100, such that the power transmissionsystem 100 may be easily disposed in a compartment of the vehicle.

In an embodiment of the present disclosure, as shown in FIG. 4, thefirst motor generator 41 is arranged coaxially with the first inputshaft 21, and the first motor generator 41 is arranged coaxially withthe engine unit 1. “The first motor generator 41 is arranged coaxiallywith the engine unit 1” would be appreciated as that a rotation axis ofa rotor of the first motor generator 41 substantially coincides with arotation axis of a crankshaft of the engine unit 1. Therefore, the powertransmission system 100 becomes more compact in structure.

In some embodiments of the present disclosure, as shown in FIGS. 2-6,the output unit 5 may include an output gear 51 and an engagement gearring 52. The output gear 51 may rotate relative to the output shaft 24,i.e. rotate differentially relative to the output shaft 24, and theengagement gear ring 52 is fixedly connected with the output gear 51,i.e. the engagement gear ring 52 rotates synchronously with the outputgear 51.

Therefore, when the synchronizer 6 needs to engage the output unit 5with the output shaft 24, the synchronizing sleeve 62 of thesynchronizer 6 may axially move toward the engagement gear ring 52, andafter the rotating speed of the output unit 5 is synchronized with therotating speed of the output shaft 24, the synchronizing sleeve 62 maybe engaged with the engagement gear ring 52 to form a rigid connectionbetween the output shaft 24, the synchronizer 6 and the output unit 5,so as to rotate the output shaft 24, the synchronizer 6 and the outputunit 5 synchronously.

In order to reduce the number of intermediate transmission components,to reduce the energy loss, and to enhance the transmission efficiency ofthe power transmission system 100, in a preferred manner, as shown inFIGS. 2-6, the output gear 51 may be a driving gear of a final drive andis configured to directly mesh with a driven gear 53 of the final driveto output the power, so as to drive the wheels 200. However, the presentdisclosure is not limited to this, and other intermediate transmissioncomponents may also be disposed between the output gear 51 and the finaldrive.

As shown in FIGS. 2-10, a differential 54 is disposed between the firstpair of wheels such as the front wheels 210. The differential 54cooperates with the output unit 5 for power transmitting. In someembodiments, the differential 54 is provided with the driven gear 53thereon, and the output gear 51 becomes the driving gear of the finaldrive configured to mesh with the driven gear 53 of the final drive,such that the power may be transferred to the two front wheels 210 viathe driving gear of the final drive, the driven gear 53 of the finaldrive and the differential 54 sequentially.

The function of the differential 54 is to properly distribute the powerto the two front wheels 210. The differential 54 may be a geardifferential, a mandatory locking differential, or the Torsendifferential, which may be selected by a person skilled in the artaccording to different vehicles.

In some embodiments of the present disclosure, as shown in FIGS. 5-7 and10, a pair of second motor generators 42 is disposed on two sides of thedifferential 54 back to back. For example, a pair of second motorgenerators 42 is disposed on two sides of the differential 54 andintegrally formed with the differential 54. For example, the left secondmotor generator 42 can be disposed between a left half shaft and theleft side of the differential 54, and the right second motor generator42 can be disposed between a right half shaft and the right side of thedifferential 54. The power transmission system 100 in FIGS. 5-7 isoperable in a four-wheel drive mode, and the power transmission system100 in FIG. 10 is operable in a two-wheel drive mode. It should be notedthat in the following, when referring to “motor generators are disposedon two sides of the differential 54 back to back,” it means that themotor generators are disposed on two sides of the differential 54respectively and integrally formed with the differential 54.

In some other embodiments of the present disclosure, as shown in FIGS.2-4 and 9, the second motor generator 42 is a wheel-side motor. In otherwords, one of the second motor generators 42 is disposed at an innerside of the left front wheel, and the other of the second motorgenerators 42 is disposed at an inner side of the right front wheel, andthe second motor generator 42 may transfer the power to a hub of acorresponding wheel via a gear mechanism. The power transmission system100 in FIGS. 2-4 is operable in a four-wheel drive mode, and the powertransmission system 100 in FIG. 9 is operable in a two-wheel drive mode.

In some embodiments of the present disclosure, two third motorgenerators 43 are provided, and the third motor generators 43 are awheel-side motor, as shown in FIGS. 2 and 5. In other words, in theexamples shown in FIGS. 2 and 5, one of the third motor generators 43 isdisposed at an inner side of the left rear wheel, the other of the thirdmotor generators 43 is disposed at an inner side of the right rearwheel, and the third motor generator 43 may transfer the power to acorresponding rear wheel via a gear mechanism.

In some other embodiments of the present disclosure, one third motorgenerator 43 is provided, and the third motor generator 43 drives thesecond pair of wheels via a first speed changing mechanism 71. The firstspeed changing mechanism 71 is preferably a reducing mechanism, and thereducing mechanism may be a one-stage or multi-stage reducing mechanism.The reducing mechanism may include, but is not limited to, a gearreducing mechanism, or a worm and worm gear reducing mechanism.

In these embodiments, the second pair of wheels may be connected witheach other via an axle which may have an integral structure. The thirdmotor generator 43 may directly drive the integral axle via the firstspeed changing mechanism 71, to drive the two wheels to rotatesynchronously.

In some more embodiments of the present disclosure, two third motorgenerators 43 are provided, and each third motor generator 43 drives oneof the second pair of wheels via a second speed changing mechanism 72.The second speed changing mechanism 72 is preferably a reducingmechanism, and the reducing mechanism may be a one-stage or multi-stagereducing mechanism. The reducing mechanism may include, but is notlimited to, a gear reducing mechanism, or a worm and worm gear reducingmechanism.

In these embodiments, the two wheels in the second pair may be connectedwith the corresponding third motor generators 43 and the correspondingsecond speed changing mechanisms 72 via two half axles respectively. Inother words, one of the third motor generators 43 may drive acorresponding half axle via one of the second speed changing mechanisms72, so as to drive the wheel at an outer side of the half axle torotate.

In some other embodiments of the present disclosure, as shown in FIGS.9-10, the power transmission system 100 is operable in a two-wheel drivemode. In an example shown in FIG. 9, the output unit 5 drives the frontwheels 210, and the second motor generator 42 is a wheel-side motor andis configured to drive the front wheels 210. In an example shown in FIG.10, the output unit 5 drives the front wheels 210, and the second motorgenerators 42 are disposed at two sides of the differential 54 back toback, for example, the second motor generators 42 are disposed at twosides of the differential 54 respectively and integrally formed with thedifferential 54. As shown in FIGS. 11-13, the power transmission system100 is operable in a four-wheel drive mode. In an example shown in FIG.11, the output unit 5 drives the front wheels 210, two second motorgenerators 42 are provided, and each second motor generator 42 drivesone rear wheel 220 via one fourth speed changing mechanism 74. In anexample shown in FIG. 12, the output unit 5 drives the front wheels 210,one second motor generator 42 is provided, and the second motorgenerator 42 drives the rear wheels 220 via one third speed changingmechanism 73. In an example shown in FIG. 13, the output unit 5 drivesthe front wheels 210, two second motor generators 42 are provided andare wheel-side motors, which are configured to drive the rear wheels220.

The third speed changing mechanism 73 may be the same as the first speedchanging mechanism 71. Similarly, the fourth speed changing mechanism 74may be the same as the second speed changing mechanism 72. Therefore,the third speed changing mechanism 73 and the fourth speed changingmechanism 74 will not be described in detail here.

In some embodiments of the present disclosure, the power transmissionsystem 100 may also include a battery component 300. The batterycomponent 300 is preferably connected with the first motor generator 41,the second motor generator 42 and the third motor generator 43respectively. Therefore, the first motor generator 41 is driven by theengine unit 1 to generate electricity or electric energy recovered bythe first motor generator 41 during the braking may be supplied to andstored in the battery component 300, and electric energy recovered bythe second motor generator 42 and the third motor generator 43 duringthe braking may also be supplied to and stored in the battery component300. When the vehicle is operated in an EV mode, the battery component300 may supply electric energy to at least one of the first motorgenerator 41, the second motor generator 42 and the third motorgenerator 43. It would be appreciated that the dot lines shown in FIG. 8indicate that the battery component 300 may be electrically connectedwith the first motor generator 41, the second motor generator 42 and thethird motor generator 43 respectively.

As an alternative embodiment of the power transmission system 100described in the foregoing embodiment, as shown in FIG. 8, the powertransmission system 100 includes input shafts, which include threeshafts, e.g. the first input shaft 21, the second input shaft 22 and thethird input shaft 23, with the second input shaft 22 being fitted overthe first input shaft 21, and the third input shaft 23 being fitted overthe second input shaft 22.

In the alternative embodiment, the power transmission system 100 furtherincludes a triple clutch 32. The triple clutch 32 has an input terminal324, a first output terminal 321, a second output terminal 322 and athird output terminal 323. The engine unit 1 is coupled with the inputterminal 324 of the triple clutch 32, the first output terminal 321 ofthe triple clutch 32 is coupled with the first input shaft 21, thesecond output terminal 322 of the triple clutch 32 is coupled with thesecond input shaft 22, and the third output terminal 323 of the tripleclutch 32 is coupled with the third input shaft 23.

Similarly, the input terminal 324 of the triple clutch 32 may be a shellthereof, and the first, second and third output terminals 321, 322, 323of the triple clutch 32 may be three driven discs. The input terminal324 may be engaged with one of the first, second and third outputterminals 321, 322, and 323, or may be disconnected with the first,second and third output terminals 321, 322, and 323. It would beappreciated that the operation principle of the triple clutch 32 issimilar to that of the dual clutch 31, so the detailed descriptionthereof will be omitted here.

In the alternative embodiment, other parts such as the powertransmitting manner between the first motor generator 41 and the firstinput shaft 21 or the output shaft 24 as well as the position and drivemode of the second motor generator 42 and the third motor generator 43,are also similar to those described in the technical solutions of thedual clutch 31, so the detailed description thereof will be omittedhere.

As another alternative embodiment of the power transmission system 100described in the foregoing embodiment, as shown in FIGS. 14-16, thepower transmission system 100 includes a driven gear 26 which isconfigured as a linked gear, and the linked gear structure 26 is freelyfitted over the output shaft 24 and rotates differentially relative tothe output shaft 24. The synchronizer 6 is disposed on the output shaft24 and may be selectively engaged with the linked gear structure 26.

In the embodiment, two input shafts are provided, e.g. the first inputshaft 21 and the second input shaft 22, and each input shaft is providedwith one driving gear 25. The linked gear structure 26 can be adouble-linked gear. The double-linked gear structure 26 has a first gearpart 261 and a second gear part 262, and the first gear part 261 and thesecond gear part 262 are configured to mesh with two driving gears 25respectively.

When the power transmission system 100 in this embodiment transmits thepower, the synchronizer 6 may be engaged with the double-linked gearstructure 26, such that the power output by at least one of the engineunit 1 and the first motor generator 41 may be output via the outputunit 5 and, e.g., the driving gear 51 of the final drive.

In these embodiments, the power transmitting between the first motorgenerator 41 and the output shaft or one of the output shafts may bedirect or indirect, and is similar to that described in the aboveembodiments, so the detailed description thereof will be omitted here.The arrangement of other components such as the clutch (e.g., the dualclutch 31 or the triple clutch 32) between the engine unit 1 and theinput shaft is similar to that described in the above embodiments, sothe detailed description thereof will also be omitted here.

In these embodiments, as shown in FIGS. 14-16, the power transmissionsystem 100 may include an engine unit 1, a plurality of input shafts, anoutput shaft 24, an output unit 5 (e.g., the driving gear 51 of thefinal drive), a synchronizer 6 and a first motor generator 41.

A main difference of these alternative embodiments from the powertransmission system 100 shown in FIGS. 2-13 is that a driven gear 26which is a linked gear and can be freely fitted over the output shaft24. With the output unit 5 fixed on the output shaft 24, thesynchronizer 6 can be configured to engage with the linked gear. Inthese embodiments, the arrangement of the first motor generator 41 mayslightly differ from that of the first motor generator 41 in the powertransmission system 100 shown in FIGS. 2-13.

In some embodiments, as shown in FIGS. 14-16, a plurality of inputshafts is provided, the input shafts are provided with the driving gears25 thereon. The linked gear structure 26 is freely fitted over theoutput shaft 24. The linked gear structure 26 has a plurality of gearparts (for example, the first gear part 261, and the second gear part262), and the gear parts are configured to mesh with the driving gears25 on the input shafts respectively.

As shown in FIGS. 14-16, the output unit 5 is configured to output thepower from the output shaft 24. For example, preferably, the output unit5 is fixed on the output shaft 24. In an embodiment of the presentdisclosure, by way of example and without limitation, the output unit 5may include the driving gear 51 of the final drive.

The synchronizer 6 is disposed on the output shaft 24. The synchronizer6 is configured to selectively engage with the linked gear structure 26,so as to output the power via the output unit 5 to drive the wheels ofthe vehicle. The power transmission between the first motor generator 41and one of the input shaft and the output shaft 24 may be direct orindirect.

In these embodiments, the function of the synchronizer 6 issubstantially the same as that of the synchronizer 6 shown in FIGS.2-13. The synchronizer 6 in these embodiments are configured to engagethe linked gear structure 26 with the output shaft 24, while thesynchronizer 6 shown in the embodiments in FIGS. 2-13 is configured toengage the output unit 5 with the output shaft 24.

In these embodiments, the function of the synchronizer 6 is toeventually synchronize the linked gear structure 26 with the outputshaft 24, so that the linked gear structure 26 and the output shaft 24can operate synchronously to output the power from at least one of theengine unit 1 and the first motor generator 41 with the output unit 5 asa power output terminal. When the linked gear structure 26 and theoutput shaft 24 are not synchronized by the synchronizer 6, the powerfrom at least one of the engine unit 1 and the first motor generator 41may not be directly output to the wheels 200 via the output unit 5.

The synchronizer 6 functions to switch the power. That is, when thesynchronizer 6 is in an engaged state, the power from at least one ofthe engine unit 1 and the first motor generator 41 may be output via theoutput unit 5 to drive the wheels 200; and when the synchronizer 6 is ina disengaged state, the power from at least one of the engine unit 1 andthe first motor generator 41 may not be transmitted to the wheels 200via the output unit 5. In this way, by controlling the synchronizer 6 toswitch between the engaged state and the disengaged state, the switchingof the drive mode of the vehicle may be realized.

Moreover, the first motor generator 41 may adjust the speed of thelinked gear structure 26 with the rotating speed of the output shaft 24as a target value, so as to match the speed of the linked gear structure26 with the speed of the output shaft 24 in a time efficient manner,thus reducing the time required by the synchronization of thesynchronizer 6 and reducing the energy loss. Meanwhile, no torqueengagement of the synchronizer 6 may be achieved, thus greatly improvingthe transmission efficiency, synchronization controllability andreal-time synchronization of the vehicle. In addition, the life of thesynchronizer 6 may be further extended, thus reducing the maintenancecost of the vehicle.

In addition, by using the linked gear structure 26, the powertransmission system 100 is more compact in structure and easy toarrange, and the number of the driven gears may be decreased so as toreduce the axial dimension of the power transmission system 100, thusreducing the cost and the arrangement difficulty.

Furthermore, the synchronizer 6 may be controlled by one separate fork,such that the control steps are simple and the reliability is high.

In some embodiments of the present disclosure, the input shafts arecoaxially nested, and each input shaft is provided with one driving gear25. In an embodiment, the input shafts include a first input shaft 21and a second input shaft 22, and each input shaft is provided with onedriving gear 25. The linked gear structure 26 is a double-linked gear,the double-linked gear structure 26 has a first gear part 261 and asecond gear part 262, and the first gear part 261 and the second gearpart 262 are configured to mesh with two driving gears 25 respectively.

A dual clutch 31 may be disposed between the engine unit 1 and the firstand second input shafts 21 and 22. For this part, reference may be madeto the dual clutch 31 in the power transmission system 100 shown inFIGS. 2 to 13. Optionally, the dual clutch 31 may be provided with adamping structure thereon. For example, the damping structure may bearranged between a first output terminal and an input terminal of thedual clutch 31, to adapt to start the vehicle at a low gear.

As shown in FIGS. 14-16, direct power transmitting and indirect powertransmitting between an output terminal of the first motor generator 41and one driving gear can be performed.

For example, the power transmission system 100 in these embodimentsfurther includes an intermediate shaft 45. A first intermediate shaftgear 451 and a second intermediate shaft gear 452 are fixed on theintermediate shaft 45. One of the first and second intermediate shaftgears 451 and 452 is configured to mesh with one driving gear 25. Forexample, as shown in FIGS. 14-15, the first intermediate shaft gear 451is configured to mesh with the driving gear 25 on the second input shaft22. Of course, the present disclosure is not limited to these examples.

In some embodiments of the present disclosure, direct power transmissionbetween the output terminal of the first motor generator 41 and one ofthe first and second intermediate shaft gears 451 and 452, or indirectpower transmission between the output terminal of the first motorgenerator 41 and one of the first and second intermediate shaft gears451 and 452 via an intermediate idler 44, can be performed. For example,as shown in FIG. 14, indirect power transmitting between the outputterminal of the first motor generator 41 and the second intermediateshaft gear 452 via an intermediate idler 44 is performed. As anotherexample, as shown in FIG. 15, the output terminal of the first motorgenerator 41 is configured to directly mesh with the second intermediateshaft gear 452 for power transmission.

As shown in FIG. 16, the output terminal of the first motor generator 41is configured to directly mesh with one gear part of the linked gearstructure 26. For example, the output terminal of the first motorgenerator 41 can be configured to directly mesh with the first gear part261 for power transmission.

However, it would be appreciated that, the present disclosure is notlimited to this. The position of the first motor generator 41 may bedesigned according to practical requirements. For example, the positionof the first motor generator 41 may be the same as that described above,or may be as shown in FIGS. 2-13, which will not be described in detailhere.

As shown in FIGS. 14-15, the first gear part 261 inputs a torque to theengine unit 1 separately, and the second gear part 262 may input atorque to the engine unit 1 and the first motor generator 41simultaneously.

As shown in FIGS. 14-16, an engagement gear ring 52 is fixed on a sideof the linked gear structure 26 facing the synchronizer 6, and thesynchronizer 6 is adapted to engage with the engagement gear ring 52,such that the linked gear structure 26 is rigidly fixed with the outputshaft 24 to rotate synchronously with the output shaft 24.

In another embodiment of the power transmission system 100 described inthe foregoing linked gear embodiment, as shown in FIGS. 17-19, in thepower transmission system 100, the synchronizer 6 in the aboveembodiments can be replaced with a clutch 9.

In these embodiments, as shown in FIGS. 17-19, the power switchingdevice is a clutch 9. The clutch 9 is adapted to enable or interrupt apower transmission between the transmission unit 2 a and the output unit5. In other words, by the engagement of the clutch 9, the transmissionunit 2 a and the output unit 5 may operate synchronously, and the outputunit 5 may output the power from the transmission unit 2 a to the wheels200. When the clutch 9 is in a disengaged state, the power output by thetransmission unit 2 a may not be directly output via the output unit 5.

In these embodiments, the double-linked gear structure 26 is freelyfitted over the output shaft 24, and the output unit 5 is fixed on theoutput shaft 24. The clutch 9 has a driving part (C_(driving) in FIG.17) and a driven part (C_(driven) in FIG. 17). One of the driving partand the driven part of the clutch 9 is disposed on a linked gearstructure such as a double-linked gear 26, and the other of the drivingpart and the driven part of the clutch 9 is disposed on the output shaft24. The driving part and the driven part of the clutch 9 may bedisengaged from or engaged with each other. For example, as shown inFIG. 17, the driving part may be disposed on the output shaft 24, andthe driven part may be disposed on the linked gear structure 26, but thepresent disclosure is not limited to this.

Therefore, after the driving part and the driven part of the clutch 9are engaged with each other, the output shaft 24 is engaged with thedouble-linked gear structure 26 freely fitted over the output shaft 24,so as to output the power via the output unit 5. After the driving partand the driven part of the clutch 9 are disengaged from each other, thelinked gear structure 26 is freely fitted over the output shaft 24, andthe output unit 5 does not transfer the power from the transmission unit2 a.

Generally speaking, for the power transmission system 100 according toembodiments of the present disclosure, since the synchronizer 6 is usedfor power switching and has advantages of small volume, simplestructure, large torque transmission and high transmission efficiency,the power transmission system 100 according to embodiments of thepresent disclosure has a reduced volume, a more compact structure andhigh transmission efficiency, and may meet the large-torque transmissionrequirements.

Meanwhile, by the speed compensation of at least one of the first motorgenerator 41, the second motor generator 42 and the third motorgenerator 43, no torque engagement of the synchronizer 6 may berealized, the ride comfort is better, the engagement speed is higher,and the dynamic response is faster. Compared to a clutch transmission inthe related art, larger torque may be withstood without failure, thusgreatly improving the stability and reliability of the transmission.

In some embodiments of the present disclosure, as shown in FIGS. 2-3, 5,6 and 8, to achieve torque distribution of the wheels, in the fiveembodiments, four motor generators are used, and each motor generator isconfigured to drive one wheel. An advantage of four independent motorsdriving the vehicle lies in that: In the related art, a mechanicalfour-wheel drive vehicle may only achieve the torque distribution offront and rear wheels, and a full-time four-wheel drive vehicle may onlyachieve small difference in instantaneous torque of left and rightwheels. However, in the foregoing five embodiments, since four motorsare used for driving the vehicle, +100% to −100% torque differenceadjustment of the left and right wheel motors may be realized, thusgreatly enhancing the steering stability during the high-speed turning,and solving the problems of understeer and oversteer. Furthermore, theturning radius of the vehicle may be greatly reduced by the rotation ofthe left and right wheels in opposite directions when the vehicle runsat a low speed, such that the vehicle is easy to operate.

The structure of the power transmission system 100 in various specificembodiments will be described below with reference to FIGS. 2-19.

Embodiment 1

As shown in FIG. 2, the engine unit 1 is coupled with the input terminal313 of the dual clutch 31, the first output terminal 311 of the dualclutch 31 is coupled with the first input shaft 21, the second outputterminal 312 of the dual clutch 31 is coupled with the second inputshaft 22, and the second input shaft 22 is coaxially fitted over thefirst input shaft 21.

Each of the first input shaft 21 and the second input shaft 22 isfixedly provided with one driving gear 25, and indirect powertransmission between the first motor generator 41 and the driving gear25 on the second input shaft 22 is performed via one intermediate gear411. The output shaft 24 is fixedly provided with two driven gears 26,and the two driven gears 26 are configured to mesh with the drivinggears 25 on the first input shaft 21 and the second input shaft 22, toform two gears.

The synchronizer 6 is disposed on the output shaft 24, the driving gear(e.g. the output gear 51) of the final drive may rotate differentiallyrelative to the output shaft 24, while the engagement gear ring 52adapted to the synchronizer 6 is fixed on a left side of the drivinggear of the final drive by using a connecting rod. The driving gear ofthe final drive is configured to externally mesh with the driven gear 53of the final drive, and the driven gear 53 of the final drive may befixed on the differential 54, to transfer the power to the differential54. The differential 54 distributes the power and adaptively transfersthe distributed power to half axles on two sides of the vehicle, todrive the wheels 200.

Two second motor generators 42 constitute wheel-side motors configuredto drive two front wheels 210 respectively, and two third motorgenerators 43 constitute wheel-side motors configured to drive two rearwheels 220 respectively. That is, in the solution, each of the fourwheels is provided with one wheel-side motor.

With the power transmission system 100 in this embodiment, by theengagement or disengagement of the dual clutch 31, the power from theengine unit 1 may be transferred to the output shaft 24 with twodifferent transmission ratios respectively. The first motor generator 41may transfer the power to the output shaft 24 with a constanttransmission ratio via a shift gear set. When the synchronizer 6 is inan engaged state, the power from the output shaft 24 may be transferredto the front wheels 210 via the final drive and the differential 54.When the synchronizer 6 is in a disengaged state, the power from theoutput shaft 24 may not be transferred to the front wheels 210. The twosecond motor generators 42 are wheel-side motors, and may directly drivetwo front wheels 210 respectively. The two third motor generators 43 arewheel-side motors, and may directly drive two rear wheels 220respectively.

The power transmission system 100 in this embodiment may have at leastthe following operating conditions: a pure electric vehicle (EV)operating condition of the third motor generator 43, a pure EVfour-wheel drive operating condition, a parallel operating condition, aseries operating condition, and a braking/decelerating feedbackoperating condition.

First Operating Condition

This operating condition is a pure EV operating condition of the thirdmotor generator 43. The dual clutch 31 is in a disengaged state, thesynchronizer 6 is in a disengaged state, the engine unit 1, the firstmotor generator 41 and the second motor generator 42 do not operate, andtwo third motor generators 43 drive two rear wheels 220 respectively.This operating condition is mainly applicable to a situation where aload is small and an electric quantity of a battery is large, forexample, during uniform motions or under urban operating conditions.

This operating condition has the advantages that since the third motorgenerators 43 directly drive the rear wheels 220, compared to afront-wheel drive vehicle, the vehicle in this embodiment has betteracceleration performance, gradeability and steering capability.Moreover, since the third motor generators 43 independently drive theleft rear wheel and the right rear wheel respectively, an electronicdifferential function may be achieved, thus increasing the operatingstability and reducing the amount of tire wear. In a front-wheel drivepart, since the association between the output gear 51 and the frontwheels 210 is interrupted by the synchronizer 6, there is no mechanicalloss in the front-wheel drive part, thus reducing the energy consumptionof the vehicle.

Second Operating Condition

This operating condition is a pure EV four-wheel drive operatingcondition. The dual clutch 31 is in a disengaged state, the synchronizer6 is in a disengaged state, the first motor generator 41 does notoperate, two second motor generators 42 are configured to drive twofront wheels 210 respectively, and two third motor generators 43 areconfigured to drive two rear wheels 220 respectively. This operatingcondition is mainly applicable to a situation where a load is large andan electric quantity of a battery is large, for example, duringacceleration, climbing, overtaking, or high-speed running.

This operating condition has the advantages of having better dynamicperformance than a single-motor drive, and having better economicefficiency and lower noise than a hybrid drive. A typical applicationhighlighting the advantages of this operating condition is trafficcongestion at a steep slope (mountain road).

Moreover, compared to a front-wheel drive vehicle and a rear-wheel drivevehicle, a pure EV four-wheel drive vehicle has better accelerationperformance, gradeability, handling performance and off-road capability.Since two second motor generators 42 and two third motor generators 43drive four wheels independently, the wheels may obtain different torquesand rotating speeds, to achieve the individual control on the fourwheels, thus maximizing the dynamic performance, operating stability andoff-road performance. Furthermore, when torques in different directionsare applied to the left and right wheels by corresponding motorgenerators, the in-situ steering of the vehicle may be realized.

Third Operating Condition

This operating condition is a parallel operating condition. The dualclutch 31 is in an engaged state, the synchronizer 6 is in an engagedstate, and the engine unit 1 and the first motor generator 41 transferthe power to the driving gear 51 of the final drive via the shift gearset and the synchronizer 6, and the driving gear 51 of the final drivetransfers the power to the front wheels 210 via the differential 54,while two second motor generators 42 transfer the power to thecorresponding front wheels 210 and two third motor generators 43transfer the power to the corresponding rear wheels 220. This operatingcondition is mainly applicable to a situation where a load is thelargest, for example, during quick acceleration, or climbing steepslopes.

This operating condition has the advantages that the five motorgenerators and the engine unit 1 drive the vehicle simultaneously, thusmaximizing the dynamic performance. Compared to a front-wheel drivevehicle and a rear-wheel drive vehicle, an HEV four-wheel drive vehiclehas better acceleration performance, gradeability, handling performanceand off-road capability. Moreover, since the third motor generators 43independently drive the left rear wheel and the right rear wheelrespectively, an electronic differential function may be achieved, and amechanical differential in the related art is avoided, thus reducingparts while increasing the handling stability and reducing the amount oftire wear.

Fourth Operating Condition

This operating condition is a series operating condition. The dualclutch 31 is in an engaged state, the synchronizer 6 is in a disengagedstate, the engine unit 1 drives the first motor generator 41 via thedual clutch 31 and the shift gear set to generate electricity, thesecond motor generators 42 are configured to drive the front wheels 210respectively, and the third motor generators 43 are configured to drivethe rear wheels 220 respectively. This operating condition is mainlyapplicable to a situation where a load is medium and an electricquantity of a battery is small.

This operating condition has the advantages that, when compared to afront-wheel drive vehicle and a rear-wheel drive vehicle, the vehicleunder the series (e.g. four-wheel drive series) operating condition hasbetter acceleration performance, gradeability, handling performance andoff-road capability. Since two second motor generators 42 and two thirdmotor generators 43 drive four wheels independently, the wheels mayobtain different torques and rotating speeds, so as to achieve theindividual control on the four wheels, thus maximizing the dynamicperformance, handling stability and off-road performance. Furthermore,when torques in different directions are applied to the left and rightwheels by corresponding motor generators, the in-situ steering of thevehicle may be realized. Moreover, the first motor generator 41 may keepthe engine unit 1 running in an optimal economic region through torqueand rotating speed adjustment, thus reducing fuel consumption during theelectricity generation.

Fifth Operating Condition

This operating condition is a braking/decelerating feedback operatingcondition. The dual clutch 31 is in an engaged state, the synchronizer 6is in a disengaged state, the engine unit 1 drives the first motorgenerator 41 to generate electricity, the second motor generators 42brake the front wheels 210 and generate electricity, and the third motorgenerators 43 brake the rear wheels 220 and generate electricity. Thisoperating condition is mainly used for braking or decelerating thevehicle.

This operating condition has the advantages that, since the second motorgenerator 42 and the third motor generator 43 brake four wheelsrespectively during the decelerating or braking, whether the vehicle isturning or moving straightly, the power of each wheel may be fullyabsorbed, in the premise of ensuring the braking force and stability ofthe vehicle, thus maximizing the energy feedback. Moreover, because ofthe disengagement of the synchronizer 6, while the four motor generatorsbrake the four wheels respectively, the engine unit 1 and the firstmotor generator 41 may continue generating electricity, so as to enablea stable electricity generation state, avoid frequent switching, andextend the life of components.

Sixth Operating Condition

This operating condition is a series-parallel operating condition. Thedual clutch 31 is in an engaged state, the synchronizer 6 is in anengaged state, a part of the power from the engine unit 1 drives thefirst motor generator 41 via the dual clutch 31 and the shift gear setto generate electricity, the other part of the power from the engineunit 1 is transferred to the driving gear 51 of the final drive via theshift gear set and the synchronizer 6, the second motor generators 42drive the front wheels 210 directly via the driving gear 51 of the finaldrive, and the third motor generators 43 drive the rear wheels 220respectively. This operating condition is mainly applicable to asituation where a load is large and an electric quantity of a battery issmall, for example, during acceleration or climbing. This operatingcondition has the advantages of exploiting all the power from the engineunit 1, ensuring the dynamic performance of the vehicle while generatingelectricity, and maintaining the electric quantity of the battery.

The above six operating conditions may be switched, and typicalswitching between operating conditions is switching from the fourthoperating condition to the third operating condition, or switching fromthe fourth operating condition to the fifth operating condition.

The switching from the fourth operating condition to the third operatingcondition will be described as follows. For example, when it isnecessary to quickly accelerate for overtaking or avoiding obstacles,according to the accelerator demand of a driver, the power transmissionsystem 100 may switch from the fourth operating condition to the thirdoperating condition. At this time, the first motor generator 41 mayadjust the rotating speed of the output shaft 24 with the rotating speedof the driving gear of the final drive as a target value through therotating speed control, so as to match the rotating speed of the outputshaft 24 with the rotating speed of the driving gear of the final driveas far as possible, thus facilitating the engagement of the synchronizer6.

During the matching, the second motor generators 42 and the third motorgenerators 43 may respond to the needs of the driver to increase thetorque, such that the vehicle is accelerated, unlike a vehicle in therelated art, the vehicle needs not to be accelerated only when thesynchronizer 6 is in an engaged state. The torque compensation inadvance may greatly shorten the torque response time and improve theinstantaneous acceleration performance of the vehicle.

As another example, the switching from the fourth operating condition tothe fifth operating condition will be described as follows. When thevehicle needs to be braked or decelerated, according to the acceleratordemand or the brake pedal operation of the driver, the powertransmission system 100 may switch from the fourth operating conditionto the fifth operating condition. The second motor generators 42 and thethird motor generators 43 may meet the braking feedback requirements,and the feedback of the first motor generator 41 is not needed. At thistime, the second motor generators 42 and the third motor generators 43may instantly respond to the needs of the driver to brake the wheels andfeedback the electric quantity, which need not be like a vehicle in therelated art which feeds back the electric quantity only when thesynchronizer 6 is in an engaged state.

Meanwhile, the engine unit 1 and the first motor generator 41 may bekept generating electricity, under the braking operating condition andthe series operating condition. The torque compensation in advance maygreatly shorten the motor braking response time and increase thefeedback electric quantity.

Under complex road conditions, for example, when the vehicle runsuphill, downhill, on a bumpy road, or under a low adhesion condition,the engagement of the synchronizer 6 can be difficult due to thechanging speed of the vehicle. Even if the first motor generator 41 mayadjust the rotating speed of the output shaft 24 through the rotatingspeed control, since the rotating speed of the driving gear of the finaldrive along with the speed of the vehicle may not be controllable, thespeed adjusting accuracy and rate of the first motor generator 41 may bereduced. Under such road conditions, since the second motor generators42 and the third motor generators 43 may compensate for the torque ofthe vehicle, the speed of the vehicle may be stabilized effectively,thus improving the driving experience of the vehicle and simplifying theengagement of the synchronizer 6.

Embodiment 2

As shown in FIG. 3, the power transmission system 100 in this embodimentdiffers from the power transmission system 100 shown in FIG. 2 in thearrangement of the third motor generators 43. In this embodiment, eachthird motor generator 43 drives a corresponding rear wheel 220 via onesecond speed changing mechanism 72. Other parts in this embodiment aresubstantially the same as those in the power transmission system 100 inthe embodiment shown in FIG. 2, so the detailed description thereof willbe omitted here. The specific operating conditions of the powertransmission system 100 in this embodiment are substantially the same asthose of the power transmission system 100 in the embodiment shown inFIG. 2, except that the power transfer between the third motorgenerators 43 and the corresponding rear wheels 220 is performed via thesecond speed changing mechanism 72, which will not be detailed here.

Embodiment 3

As shown in FIG. 4, the power transmission system 100 in this embodimentdiffers from the power transmission system 100 shown in FIG. 2 in thearrangement of the third motor generators 43. In this embodiment, onethird motor generator 43 is provided and drives the rear wheels 220 viaone first speed changing mechanism 71. Other parts in this embodimentare substantially the same as those in the power transmission system 100in the embodiment shown in FIG. 2, so the detailed description thereofwill be omitted here. The specific operating conditions of the powertransmission system 100 in this embodiment are substantially the same asthose of the power transmission system 100 in the embodiment shown inFIG. 2, except that since two rear wheels 220 are driven by one thirdmotor generator 43 and one first speed changing mechanism 71, in thepremise of no new components, the differential function of the rearwheels 220 may not be realized by means of only one motor and one speedchanging mechanism, however, it would be appreciated that a differentialintegrally formed with the first speed changing mechanism 71 may beadded to realize the differential rotation of the two rear wheels 220.

Embodiment 4

As shown in FIG. 5, the power transmission system 100 in this embodimentdiffers from the power transmission system 100 shown in FIG. 2 in thearrangement of the second motor generators 42. In this embodiment, thesecond motor generators 42 are disposed at two sides of the differential54 back to back respectively. Other parts in this embodiment aresubstantially the same as those in the power transmission system 100 inthe embodiment shown in FIG. 2, so the detailed description thereof willbe omitted here. The specific operating conditions of the powertransmission system 100 in this embodiment are substantially the same asthose of the power transmission system 100 in the embodiment shown inFIG. 2, which will not be detailed here.

Embodiment 5

As shown in FIG. 6, the power transmission system 100 in this embodimentdiffers from the power transmission system 100 shown in FIG. 5 in thearrangement of the third motor generators 43. In this embodiment, eachthird motor generator 43 drives a corresponding rear wheel 220 via onesecond speed changing mechanism 72. Other parts in this embodiment aresubstantially the same as those in the power transmission system 100 inthe embodiment shown in FIG. 2, so the detailed description thereof willbe omitted here. The specific operating conditions of the powertransmission system 100 in this embodiment are substantially the same asthose of the power transmission system 100 in the embodiment shown inFIG. 2, which will not be detailed here.

Embodiment 6

As shown in FIG. 7, the power transmission system 100 in this embodimentdiffers from the power transmission system 100 shown in FIG. 5 in thearrangement of the third motor generators 43. In this embodiment, onethird motor generator 43 is provided and drives the rear wheels 220 viaone first speed changing mechanism 71. Other parts in this embodimentare substantially the same as those in the power transmission system 100in the embodiment shown in FIG. 5, so the detailed description thereofwill be omitted here. The specific operating conditions of the powertransmission system 100 in this embodiment are substantially the same asthose of the power transmission system 100 in the embodiment shown inFIG. 5, except that since two rear wheels 220 are driven by one thirdmotor generator 43 and one first speed changing mechanism 71, in thepremise of no new components, the differential function of the rearwheels 220 may not be realized by means of only one motor and one speedchanging mechanism, however, it would be appreciated that a differentialintegrally formed with the first speed changing mechanism 71 may beadded to realize the differential rotation of the two rear wheels 220.

Embodiment 7

As shown in FIG. 8, the power transmission system 100 in this embodimentdiffers from the power transmission system 100 shown in FIG. 2 in thetype of the clutch as well as the number of the input shafts, thedriving gears 25 and the driven gears 26. In this embodiment, the clutchis a triple clutch 32, three input shafts are provided, andcorrespondingly three pairs of driving gears 25 and driven gears 26 areprovided. Other parts in this embodiment are substantially the same asthose in the power transmission system 100 in the embodiment shown inFIG. 2, so the detailed description thereof will be omitted here.

Embodiment 8

As shown in FIG. 9, the power transmission system 100 in this embodimentdiffers from the power transmission system 100 shown in FIG. 2 in thatthe third motor generators 43 in the embodiment shown in FIG. 2 areeliminated, and the power transmission system 100 in this embodiment isoperable in a two-wheel drive mode.

The power transmission system 100 in this embodiment may have at leastthe following operating conditions.

First Operating Condition

This operating condition is a pure EV operating condition of the secondmotor generator 42. The dual clutch 31 is in a disengaged state, thesynchronizer 6 is in a disengaged state, the engine unit 1 and the firstmotor generator 41 do not operate, and the second motor generators 42drive the front wheels 210 directly. This operating condition is mainlyapplicable to a situation where a load is small and an electric quantityof a battery is large, for example, during uniform motions or underurban operating conditions.

This operating condition has the advantages that, since the second motorgenerators 42 directly drive the front wheels 210, the transmissionchain is the shortest, and operating components are the fewest, thusachieving maximum transmission efficiency and minimum noise. Moreover,since the second motor generators 42 independently drive the left frontwheel 210 and the right front wheel 210 respectively, an electronicdifferential function may be achieved, thus increasing the handlingstability and reducing the amount of tire wear.

Second Operating Condition

This operating condition is a pure EV operating condition of threemotors. The dual clutch 31 is in a disengaged state, the synchronizer 6is in an engaged state, the engine unit 1 does not operate, the firstmotor generator 41 transfers the power to the driving gear 51 of thefinal drive via the shift gear set and the synchronizer 6, and thedriving gear 51 of the final drive evenly distributes the power to theleft and right front wheels 210 via the differential 54, while thesecond motor generators 42 directly drive the left and right frontwheels 210.

This operating condition is mainly applicable to a situation where aload is large and an electric quantity of a battery is large, forexample, during acceleration, climbing, overtaking, or high-speedrunning. This operating condition has the advantages of having betterdynamic performance than a single-motor drive, and having bettereconomic efficiency and lower noise than a hybrid drive. A typicalapplication highlighting the advantages of this operating condition istraffic congestion at a steep slope (mountain road).

Third Operating Condition

This operating condition is a parallel operating condition. The dualclutch 31 is in a disengaged state, the synchronizer 6 is in an engagedstate, the engine unit 1 and the first motor generator 41 transfer thepower to the driving gear 51 of the final drive via the shift gear setand the synchronizer 6, the driving gear 51 of the final drive evenlydistributes the power to the left and right front wheels via thedifferential 54, and the second motor generators 42 directly drive theleft and right front wheels. This operating condition is mainlyapplicable to a situation where a load is the largest, for example,during quick acceleration, or climbing steep slopes.

This operating condition has the advantages that three motors and theengine unit 1 drive the vehicle simultaneously, thus maximizing thedynamic performance.

Fourth Operating Condition

This operating condition is a series operating condition. The dualclutch 31 is in an engaged state, the synchronizer 6 is in a disengagedstate, the engine unit 1 drives the first motor generator 41 via thedual clutch 31 and the shift gear set to generate electricity, thesecond motor generators 42 directly drive the wheels. This operatingcondition is mainly applicable to a situation where a load is medium andan electric quantity of a battery is small.

This operating condition has the advantages that, since the second motorgenerators 42 directly drive the wheels, the transmission chain is theshortest, and operating components are the fewest, thus achievingmaximum transmission efficiency and minimum noise.

Meanwhile, the first motor generator 41 may keep the engine unit 1running in an optimal economic region through torque and rotating speedadjustment, thus reducing fuel consumption during the electricitygeneration. Moreover, since the second motor generators 42 independentlydrive the left front wheel and the right front wheel respectively, anelectronic differential function may be achieved, thus increasing thehandling stability and reducing the amount of tire wear.

Fifth Operating Condition

This operating condition is a braking/decelerating feedback operatingcondition. The dual clutch 31 is in an engaged state, the synchronizer 6is in a disengaged state, the engine unit 1 drives the first motorgenerator 41 to generate electricity, and the second motor generator 42directly brakes the wheels and generates electricity. This operatingcondition is mainly used for braking or decelerating the vehicle. Thisoperating condition has the advantages that, since the second motorgenerator 42 brake two wheels respectively during the decelerating orbraking of the vehicle, the braking energy may be absorbed to thelargest extent and converted into electric energy, and the engine unit 1and the first motor generator 41 may continue generating electricity, toenable a stable electricity generation state and avoid frequentswitching.

The above five operating conditions may be switched, and typicalswitching between operating conditions is switching from the fourthoperating condition to the third operating condition, or switching fromthe fourth operating condition to the fifth operating condition.

The switching from the fourth operating condition to the third operatingcondition will be described as follows. For example, when it isnecessary to quickly accelerate for overtaking or avoiding obstacles,according to the accelerator demand of a driver, the power transmissionsystem may switch from the fourth operating condition to the thirdoperating condition. At this time, the first motor generator 41 mayadjust the rotating speed of the output shaft 24 with the rotating speedof the driving gear 51 of the final drive as a target value through therotating speed control, so as to match the rotating speed of the outputshaft 24 with the rotating speed of the driving gear 51 of the finaldrive as far as possible, thus facilitating the engagement of thesynchronizer 6. During the matching, the second motor generators 42 mayrespond to the needs of the driver to increase the torque, such that thevehicle is accelerated, unlike a vehicle in the related art, the vehicledoes not require the synchronizer 6 to be in an engaged state in orderto be accelerated. The torque compensation in advance may greatlyshorten the torque response time and improve the instantaneousacceleration performance of the vehicle.

For example, the switching from the fourth operating condition to thefifth operating condition will be described as follows. When the vehicleneeds to be braked or decelerated, according to the accelerator demandor the brake pedal operation of the driver, the power transmissionsystem 100 may switch from the fourth operating condition to the fifthoperating condition. The second motor generators 42 may meet the brakingfeedback requirements, and the feedback of the first motor generator 41is not needed. At this time, the second motor generators 42 mayinstantly respond to the needs of the driver to brake the wheels andfeedback the electric quantity, unlike a vehicle in the related art, thevehicle does not require the synchronizer 6 to be in an engaged state tofeedback the electric quantity.

Meanwhile, the engine unit 1 and the first motor generator 41 may bekept generating electricity, under the braking operating condition andthe series operating condition. The torque compensation in advance maygreatly shorten the motor braking response time and increase thefeedback electric quantity.

Under complex road conditions, for example, when the vehicle runsuphill, downhill, on a bumpy road, or under a low adhesion condition,the engagement of the synchronizer 6 is difficult due to the changingspeed of the vehicle. Even if the first motor generator 41 may adjustthe rotating speed of the output shaft 24 through the rotating speedcontrol, since the rotating speed of the driving gear of the final drivealong with the speed of the vehicle is not controllable, the speedadjusting accuracy and rate of the first motor generator 41 may bereduced. Under these road conditions, since the second motor generators42 may compensate for the torque of the vehicle, the speed of thevehicle may be stabilized effectively, thus improving the drivingexperience of the vehicle and simplifying the engagement of thesynchronizer 6.

Embodiment 9

As shown in FIG. 10, the power transmission system 100 in thisembodiment differs from the power transmission system 100 shown in FIG.9 in the arrangement of the second motor generators 42. In thisembodiment, the second motor generators 42 are disposed at two sides ofthe differential 54 back to back respectively. Other parts in thisembodiment are substantially the same as those in the power transmissionsystem 100 in the embodiment shown in FIG. 9, so the detaileddescription thereof will be omitted here.

Embodiment 10

As shown in FIG. 11, the power transmission system 100 in thisembodiment differs from the power transmission system 100 shown in FIG.9 in the arrangement of the second motor generators 42. In thisembodiment, two second motor generators 42 are provided, and each secondmotor generator 42 drives a corresponding rear wheel 220 via one fourthspeed changing mechanism 74. Other parts in this embodiment aresubstantially the same as those in the power transmission system 100 inthe embodiment shown in FIG. 9, so the detailed description thereof willbe omitted here.

The power transmission system 100 in this embodiment may have at leastthe following operating conditions.

First Operating Condition

This operating condition is a pure EV operating condition of the secondmotor generator 42. The dual clutch 31 is in a disengaged state, thesynchronizer 6 is in a disengaged state, the engine unit 1 and the firstmotor generator 41 do not operate, and each second motor generator 42drives one rear wheel via a corresponding fourth speed changingmechanism 74. This operating condition is mainly applicable to asituation where a load is small and an electric quantity of a battery islarge, for example, during uniform motions or under urban operatingconditions. This operating condition has the advantages that, since thesecond motor generators 42 drive the rear wheels, compared to afront-wheel drive vehicle, the vehicle in this embodiment has betteracceleration performance, gradeability and steering capability.Moreover, since the second motor generators 42 independently drive theleft rear wheel and the right rear wheel respectively, an electronicdifferential function may be achieved, thus increasing the handlingstability and reducing the amount of tire wear. In a front-wheel drivepart, since the association between the gear set and the front wheels isinterrupted by the synchronizer 6, there is no mechanical loss in thefront-wheel drive part, thus reducing the energy consumption of thevehicle.

Second Operating Condition

This operating condition is a pure EV four-wheel drive operatingcondition. The dual clutch 31 is in a disengaged state, the synchronizer6 is in an engaged state, the engine unit 1 does not operate, the firstmotor generator 41 drives the front wheels respectively, and the secondmotor generators 42 drive the rear wheels respectively. This operatingcondition is mainly applicable to a situation where a load is large andan electric quantity of a battery is large, for example, duringacceleration, climbing, overtaking, or high-speed running. Thisoperating condition has the advantages of having better dynamicperformance than a single-motor drive, and having better economicefficiency and lower noise than a hybrid drive. A typical applicationhighlighting the advantages of this operating condition is trafficcongestion at a steep slope (mountain road). Moreover, compared to afront-wheel drive vehicle and a rear-wheel drive vehicle, a pure EVfour-wheel drive vehicle has better acceleration performance,gradeability, handling performance and off-road capability. Moreover,since the second motor generators 42 independently drive the left rearwheel and the right rear wheel respectively, an electronic differentialfunction may be achieved, thus increasing the handling stability andreducing the amount of tire wear.

Third Operating Condition

This operating condition is a parallel operating condition. The dualclutch 31 is in a disengaged state, the synchronizer 6 is in an engagedstate, the engine unit 1 and the first motor generator 41 drive thefront wheels 210 simultaneously, and the second motor generators 42drive the rear wheels respectively. This operating condition is mainlyapplicable to a situation where a load is the largest, for example,during quick acceleration, or climbing steep slopes. This operatingcondition has the advantages that two motor generators and the engineunit drive the vehicle simultaneously, thus maximizing the dynamicperformance. Compared to a front-wheel drive vehicle and a rear-wheeldrive vehicle, an HEV four-wheel drive vehicle has better accelerationperformance, gradeability, handling performance and off-road capability.Moreover, since the second motor generators 42 independently drive theleft rear wheel and the right rear wheel respectively, an electronicdifferential function may be achieved, thus increasing the handlingstability and reducing the amount of tire wear.

Fourth Operating Condition

This operating condition is a series operating condition. The dualclutch 31 is in an engaged state, the synchronizer 6 is in a disengagedstate, the engine unit 1 drives the first motor generator 41 to generateelectricity, and the second motor generators 42 drive the rear wheelsrespectively. This operating condition is mainly applicable to asituation where a load is medium and an electric quantity of a batteryis small. This operating condition has the advantages that, since thetwo second motor generators independently drive the left rear wheel andthe right rear wheel respectively, an electronic differential functionmay be achieved, thus increasing the handling stability and reducing theamount of tire wear. Compared to a front-wheel drive vehicle, thevehicle under the series operating condition has better accelerationperformance, gradeability, and steering capability. Moreover, the firstmotor generator 41 may keep the engine unit 1 running in an optimaleconomic region through torque and rotating speed adjustment, thusreducing fuel consumption during the electricity generation.

Fifth Operating Condition

This operating condition is a braking/decelerating feedback operatingcondition. The dual clutch 31 is in a disengaged state, the synchronizer6 is in an engaged state, the engine unit does not operate, and thefirst motor generator and the second motor generators brake the vehicleand generate electricity simultaneously. This operating condition hasthe advantages that, since three motors brake the vehicle simultaneouslyduring the decelerating or braking of the vehicle, the braking energymay be absorbed to the largest extent and converted into electricenergy. By the disengagement of the dual clutch, the braking of thevehicle by the friction torque of the engine unit may be eliminated, sothat more power is left to be absorbed by the motor. Because of thebraking feedback of the front-wheel drive and the rear-wheel drive, thebraking force may be distributed to front and rear motors in the premiseof ensuring the braking force of the vehicle, and more electric energymay be fed back compared to a front-wheel drive vehicle or a rear-wheeldrive vehicle. Moreover, two second motor generators may control thebraking force independently, thus improving the handling stability ofthe vehicle during braking when turning, and further increasing thefeedback energy.

Similarly, the operating conditions of the power transmission system 100in this embodiment may be switched, and typical switching betweenoperating conditions is switching from the fourth operating condition tothe third operating condition, or switching from the fourth operatingcondition to the fifth operating condition. The switching between theoperating conditions of the power transmission system 100 in thisembodiment is similar to that in the above embodiments, so the detaileddescription thereof will be omitted here.

Embodiment 11

As shown in FIG. 12, the power transmission system 100 in thisembodiment differs from the power transmission system 100 shown in FIG.9 in the arrangement of the second motor generators 42. In thisembodiment, one second motor generators 42 is provided, and the secondmotor generator 42 drives the rear wheels 220 via one third speedchanging mechanism 73. Other parts in this embodiment are substantiallythe same as those in the power transmission system 100 in the embodimentshown in FIG. 9, so the detailed description thereof will be omittedhere.

In this embodiment, the second motor generator 42 may be used to drivethe vehicle separately. At this time, the dual clutch 31 and thesynchronizer 6 are in a disengaged state. This operating condition ismainly applicable to a situation where a load is small and an electricquantity of a battery is large, for example, during uniform motions orunder urban operating conditions. This operating condition has theadvantages that, since the second motor generators 42 directly drive therear wheels 220 via the third speed changing mechanism 73, compared to afront-wheel drive vehicle, the vehicle in this embodiment has betteracceleration performance, gradeability and steering capability. In afront-wheel drive part, the synchronizer 6 is in a disengaged state, sothere is no mechanical loss in the front-wheel drive part, thus reducingthe energy consumption of the vehicle. In a rear-wheel drive part, adifferential integrally formed with the third speed changing mechanism73 may also be added.

In this embodiment, the power transmission system 100 may also have apure EV four-wheel drive operating condition. At this time, the dualclutch 31 is in a disengaged state, the synchronizer 6 is in an engagedstate, the engine unit 1 does not operate, the first motor generator 41drives the front wheels 210 respectively, and the second motor generator42 drives the rear wheels 220 respectively. This operating condition ismainly applicable to a situation where a load is large and an electricquantity of a battery is large, for example, during acceleration,climbing, overtaking, or high-speed running. This operating conditionhas better dynamic performance than a single-motor drive, and has bettereconomic efficiency and lower noise than a hybrid drive. A typicalapplication highlighting the advantages of this operating condition istraffic congestion at a steep slope (mountain road). Moreover, comparedto a front-wheel drive vehicle and a rear-wheel drive vehicle, a pure EVfour-wheel drive vehicle has better acceleration performance,gradeability, handling performance and off-road capability.

In this embodiment, the power transmission system may also have aparallel operating condition. The dual clutch 31 is in an engaged state,the synchronizer 6 is in an engaged state, the engine unit 1 and thefirst motor generator 41 drive the front wheels 210 simultaneously, andthe second motor generator 42 drives the rear wheels 220. This operatingcondition is mainly applicable to a situation where a load is thelargest, for example, during quick acceleration, or climbing steepslopes. This operating condition has the advantages that two motors andthe engine unit 1 drive the vehicle simultaneously, thus maximizing thedynamic performance. Compared to a front-wheel drive vehicle and arear-wheel drive vehicle, an HEV four-wheel drive vehicle has betteracceleration performance, gradeability, handling performance andoff-road capability.

In this embodiment, the power transmission system may also have a seriesoperating condition. The dual clutch 31 is in an engaged state, thesynchronizer 6 is in a disengaged state, the engine unit 1 drives thefirst motor generator 41 to generate electricity, and the second motorgenerator drives the rear wheels. This operating condition is mainlyapplicable to a situation where a load is medium and an electricquantity of a battery is small. This operating condition has theadvantages that the second motor generator 42 drives the rear wheels,and compared to a front-wheel drive vehicle, the vehicle under theseries operating condition has better acceleration performance,gradeability and steering capability. Moreover, the first motorgenerator 41 may keep the engine unit 1 running in an optimal economicregion through torque and rotating speed adjustment, thus reducing fuelconsumption during the electricity generation.

In this embodiment, the power transmission system may also have abraking/decelerating feedback operating condition. The dual clutch 31 isin a disengaged state, the synchronizer 6 is in an engaged state, theengine unit 1 does not operate, and the first motor generator 41 and thesecond motor generator 42 brake the vehicle and generate electricitysimultaneously. This operating condition has the advantages that, sincetwo motors brake the vehicle simultaneously during the decelerating orbraking of the vehicle, the braking energy may be absorbed to thelargest extent and converted into electric energy. By the disengagementof the dual clutch 31, the braking of the vehicle by the friction torqueof the engine unit may be eliminated, so that more power is left to beabsorbed by the motor. Because of the braking feedback of thefront-wheel drive and the rear-wheel drive, the braking force may bedistributed to front and rear motors in the premise of ensuring thebraking force of the vehicle, and more electric energy may be fed backcompared to a front-wheel drive vehicle or a rear-wheel drive vehicle.

Similarly, the operating conditions of the power transmission system 100in this embodiment may be switched, and typical switching betweenoperating conditions is switching from the fourth operating condition tothe third operating condition, or switching from the fourth operatingcondition to the fifth operating condition. The switching between theoperating conditions of the power transmission system 100 in thisembodiment is similar to that in the above embodiments, so the detaileddescription thereof will be omitted here.

Embodiment 12

As shown in FIG. 13, the power transmission system 100 in thisembodiment differs from the power transmission system 100 shown in FIG.9 in the arrangement of the second motor generators 42. In thisembodiment, two second motor generators 42 are provided and arewheel-side motors, and each second motor generator 42 drives acorresponding rear wheel 220. Other parts in this embodiment aresubstantially the same as those in the power transmission system 100 inthe embodiment shown in FIG. 9, so the detailed description thereof willbe omitted here.

Embodiment 13

As shown in FIG. 14, the engine unit 1 is coupled with the inputterminal 313 of the dual clutch 31, the first output terminal 311 of thedual clutch 31 is coupled with the first input shaft 21, the secondoutput terminal 312 of the dual clutch 31 is coupled with the secondinput shaft 22, and the second input shaft 22 is coaxially fitted overthe first input shaft 21.

Each of the first input shaft 21 and the second input shaft 22 isprovided with one driving gear 25 by fixing, the double-linked gearstructure 26 (i.e. a driven gear) is freely fitted over the output shaft24, the first gear part 261 of the double-linked gear structure 26 isconfigured to mesh with the driving gear 25 on the first input shaft 21,and the second gear part 262 of the double-linked gear structure 26 isconfigured to mesh with the driving gear 25 on the second input shaft22.

A first intermediate shaft gear 451 and a second intermediate shaft gear452 are fixed on the intermediate shaft 45. The first intermediate shaftgear 451 is configured to mesh with the driving gear 25 on the secondinput shaft 22. Indirect power transmitting between the output terminalof the first motor generator 41 and the second intermediate shaft gear452 via an intermediate idler 44 is performed.

The synchronizer 6 is disposed on the output shaft 24 and configured toengage with the double-linked gear structure 26. The driving gear 51 ofthe final drive is fixed on the output shaft 24. The driving gear 51 ofthe final drive is configured to externally mesh with the driven gear 53of the final drive, and the driven gear 53 of the final drive may befixed on a shell of the differential 54, so as to transfer the power tothe differential 54. The differential 54 distributes the power andadaptively transfers the distributed power to half axles at two sides ofthe vehicle, so as to drive the wheels 200.

Embodiment 14

As shown in FIG. 15, the engine unit 1 is coupled with the inputterminal 313 of the dual clutch 31, the first output terminal 311 of thedual clutch 31 is coupled with the first input shaft 21, the secondoutput terminal 312 of the dual clutch 31 is coupled with the secondinput shaft 22, and the second input shaft 22 is coaxially fitted overthe first input shaft 21.

Each of the first input shaft 21 and the second input shaft 22 isprovided with one driving gear 25, the double-linked gear structure 26(i.e. a driven gear) is freely fitted over the output shaft 24, thefirst gear part 261 of the double-linked gear structure 26 is configuredto mesh with the driving gear 25 on the first input shaft 21, and thesecond gear part 262 of the double-linked gear structure 26 isconfigured to mesh with the driving gear 25 on the second input shaft22.

A first intermediate shaft gear 451 and a second intermediate shaft gear452 are fixed on the intermediate shaft 45. The first intermediate shaftgear 451 is configured to mesh with the driving gear 25 on the secondinput shaft 22. The output terminal of the first motor generator 41 isconfigured to directly mesh with the second intermediate shaft gear 452for power transmitting.

The synchronizer 6 is disposed on the output shaft 24 and is configuredto engage with the double-linked gear structure 26. The driving gear 51of the final drive is fixed on the output shaft 24. The driving gear 51of the final drive is configured to externally mesh with the driven gear53 of the final drive, and the driven gear 53 of the final drive may befixed on a shell of the differential 54, so as to transfer the power tothe differential 54. The differential 54 distributes the power andadaptively transfers the distributed power to half axles at two sides ofthe vehicle, so as to drive the wheels 200.

Embodiment 15

As shown in FIG. 16, the engine unit 1 is coupled with the inputterminal 313 of the dual clutch 31, the first output terminal 311 of thedual clutch 31 is coupled with the first input shaft 21, the secondoutput terminal 312 of the dual clutch 31 is coupled with the secondinput shaft 22, and the second input shaft 22 is coaxially fitted overthe first input shaft 21.

Each of the first input shaft 21 and the second input shaft 22 isprovided with one driving gear 25, the double-linked gear structure 26(i.e. a driven gear) is freely fitted over the output shaft 24, thefirst gear part 261 of the double-linked gear 26 is configured to meshwith the driving gear 25 on the first input shaft 21, and the secondgear part 262 of the double-linked gear 26 is configured to mesh withthe driving gear 25 on the second input shaft 22. The output terminal ofthe first motor generator 41 is configured to directly mesh with thefirst gear part 261 for power transmitting.

The synchronizer 6 is disposed on the output shaft 24 and configured toengage with the double-linked gear 26. The driving gear 51 of the finaldrive is fixed on the output shaft 24. The driving gear 51 of the finaldrive is configured to externally mesh with the driven gear 53 of thefinal drive, and the driven gear 53 of the final drive may be fixed on ashell of the differential 54, so as to transfer the power to thedifferential 54. The differential 54 distributes the power andadaptively transfers the distributed power to half axles at two sides ofthe vehicle, so as to drive the wheels 200.

Embodiment 16

As shown in FIG. 17, the power transmission system 100 in thisembodiment differs from the power transmission system 100 shown in FIG.14 in that the clutch 9 is provided instead of the synchronizer 6 of thepower transmission system 100 in FIG. 14, and the driving gear 51 of thefinal drive is fixed on the output shaft 24.

Embodiment 17

As shown in FIG. 18, the power transmission system 100 in thisembodiment differs from the power transmission system 100 shown in FIG.15 in that the clutch 9 is provided instead of the synchronizer 6 of thepower transmission system 100 in FIG. 15, and the driving gear 51 of thefinal drive is fixed on the output shaft 24.

Embodiment 18

As shown in FIG. 19, the power transmission system 100 in thisembodiment differs from the power transmission system 100 shown in FIG.16 in that the clutch 9 is provided instead of the synchronizer 6 of thepower transmission system 100 in FIG. 16, and the driving gear 51 of thefinal drive is fixed on the output shaft 24.

It should be noted that, as shown in FIGS. 14-19, in an alternativeembodiment of the linked gear structure 26, the power transmissionsystem 100 may further include the second motor generator 42 and thethird motor generator 43 or only include the third motor generator 43(not shown in FIGS. 14-19), and the arrangement of the second motorgenerator 42 and the third motor generator 43 may be the same as that inFIGS. 2-13, for example, being in a wheel-side form, or being disposedat two sides of the differential back to back. For example, as anoptional embodiment, the driving gear 51 of the final drive of the powertransmission system 100 shown in FIGS. 14-19 may be configured to drivethe front wheels 210, and the rear-wheel drive may be the same as thatshown in FIG. 12, i.e. the rear wheels 220 are driven by one secondmotor generator 42 and one reducing mechanism.

In addition, embodiments of the present disclosure further provide avehicle including the abovementioned power transmission system 100. Itwould be appreciated that, other components (e.g., a driving system, asteering system, and a braking system) of the vehicle according toembodiments of the present disclosure are well known to those skilled inthe art, so the detailed description thereof will be omitted here.

Based on the power transmission system and the vehicle having the powertransmission system that are described in the above embodiments,embodiments of the present disclosure provide a vehicle and a brakingfeedback control method for the same, where the braking feedback controlmethod for a vehicle In some embodiments of the present disclosure isexecuted based on the power transmission system and the vehicle havingthe power transmission system that are described in the aboveembodiments.

FIG. 20 is a flowchart of a braking feedback control method for avehicle according to an embodiment of the present disclosure. Thevehicle In some embodiments of the present disclosure includes the powertransmission system described in the foregoing embodiment, so that thevehicle includes an engine unit, a transmission unit adapted toselectively couple with the engine unit and also configured to transmitthe power generated by the engine unit, a first motor generator coupledwith the transmission unit, an output unit, a power switching device, asecond motor generator configured to drive at least one of front andrear wheels of the vehicle, and a power battery for supplying power tothe first motor generator and the second motor generator, where theoutput unit is configured to transmit the power transmitted by thetransmission unit to at least one of the front and rear wheels of thevehicle, and the power switching device is adapted to enable orinterrupt power transmission between the transmission unit and theoutput unit.

According to an embodiment of the present disclosure, the powerswitching device is configured as a synchronizer, and the synchronizeris adapted to selectively synchronize between the output unit and thetransmission unit.

FIG. 21 is a schematic view of an energy transfer path of a powertransmission system of a vehicle according to an embodiment of thepresent disclosure. As shown in FIG. 21, when the power transmissionsystem works in a series mode, the engine unit 1 drives a front motor,that is, a first motor generator 41 via a clutch C2 (engagement) togenerate electricity, the electricity is provided to a rear motor thatis, a second motor generator 42 for driving and use, and an energytransfer path is, for example, a path 101. When the power transmissionsystem works in a parallel mode, the engine unit 1 transfers the powerof the engine unit 1 to a transmission T (gear 3 or gear 6) via a clutchC1 or C2 (engagement with either clutch), and eventually the power istransferred to the wheels by using a synchronizer S. Meanwhile, themotor, that is, the first motor generator 41 transfers the power to thewheels by using the transmission T and the synchronizer S, and theenergy transfer path is any one of the paths 102 and the path 103. Whenthe power transmission system works in a series-parallel mode, theengine unit 1 drives the wheels via a parallel mode path, the remainingpower is used to generate electricity by using a series mode path andsupply the electricity to the rear motor, that is, the second motorgenerator 42 for driving and use, and the energy transfer path is thepath 101, the path 102 (any one of the paths 102), and the path 103.

FIG. 22 is a diagram of information interaction of braking feedbackcontrol of a vehicle according to an embodiment of the presentdisclosure. As shown in FIG. 22, a driving motor collects a motorresolver signal and a temperature signal by using sensors and transfersthe motor resolver signal and the temperature signal to a motorcontroller ECN; a battery management system (BMS) sends a rechargeablepower signal to the ECN; an electronic stability program module ESCcollects the speed of the vehicle and a state signal of an anti-lockbraking system (ABS) and transfers the speed of the vehicle and thestate signal of the ABS system to the ECN; the ECN determines, accordingto input signals (signals such as the depth of the braking pedal, andthe slope of the road), whether to enter/exit a braking feedback controlmode, performs braking feedback control according to a formulatedfeedback strategy, and at the same time sends a target torque signal ofan engine unit to an ECM, sends a motor driving signal to the drivingmotor, and sends a vehicle energy status signal to a combination meter,and the like.

Therefore, as shown in FIG. 20, the braking feedback control method fora vehicle includes the following steps:

S1: Detect the current speed of the vehicle and the depth of a brakingpedal of the vehicle.

S2: When the current speed of the vehicle is greater than a presetspeed, the depth of the braking pedal is greater than 0, and ananti-lock braking system (ABS) of the vehicle is in a non-working state,control the vehicle to enter a braking feedback control mode, where whenthe vehicle is in the braking feedback control mode, a required brakingtorque corresponding to the vehicle is obtained according to the depthof the braking pedal (the required braking torque of the vehiclecorresponds to the depth of the braking pedal), and a braking torque ofthe first motor generator, a braking torque of the second motorgenerator, and a braking torque of basic braking performed on thevehicle are distributed according to the required braking torque. Itshould be noted that, the basic braking is mechanical friction brakingof the vehicle. Moreover, when a braking torque is distributed amongseveral braking sources, a proportion of an electric braking torqueshould be maximized under the premise of ensuring the brakingperformance and the ride comfort of the vehicle, that is, thedistribution of the braking torque of the basic braking should beminimized.

FIG. 23 is a flowchart of a vehicle entering a braking feedback controlmode according to an embodiment of the present disclosure. As shown inFIG. 23, a procedure of the vehicle entering a braking feedback controlmode includes:

S1001: Determine whether the speed of the vehicle is greater than apreset speed Vmin. If yes, perform Step S1002; or if not, perform StepS1005.

S1002: Determine whether the depth of the braking pedal is greater than0. If yes, perform Step S1003; or if not, perform Step S1005.

S1003: Determine whether the ABS does not operate. If yes, perform StepS1004; or if not, perform Step S1005.

S1004: The vehicle enters braking feedback control, that is, controlsthe vehicle to enter the braking feedback control mode.

S1005: The vehicle does not enter braking feedback control.

In other words, it is determined by using an input signal whether thevehicle meets a condition of entering braking feedback control, and themeeting the condition to enter braking feedback control is: The speed ofthe vehicle>Vmin, the depth of the braking pedal>0, and the ABS is in anon-working state, while the vehicle may be in any gear; in contrast,when any one condition is not met (that is, the speed of the vehicle isless than or equal to Vmin or the depth of the braking pedal is lessthan or equal to 0 or the ABS is in a working state), the vehicle doesnot enter braking feedback control.

According to an embodiment of the present disclosure, when the vehicleis in the braking feedback control mode, a feedback limit value of thefirst motor generator and a feedback limit value of the second motorgenerator are obtained according to current running states of the firstmotor generator and the second motor generator; a feedback limit valueof the motor generator controller is obtained according to a currentrunning state of a motor generator controller of the vehicle; a currentallowable charging power of the power battery is calculated according toa working state of the power battery, and a current feedback limit valueof the power battery is obtained according to the current allowablecharging power of the power battery; and a minimum feedback limit valueof the feedback limit value of the first motor generator, the feedbacklimit value of the second motor generator, the feedback limit value ofthe motor generator controller, and the current feedback limit value ofthe power battery is obtained.

It should be noted that the feedback limit value of the first motorgenerator refers to a braking feedback torque value that is allowed bythe first motor generator and is obtained through calculation accordingto the running state (such as the temperature, current, and voltage) ofthe first motor generator during braking feedback control of thevehicle. Similarly, the feedback limit value of the second motorgenerator refers to a braking feedback torque value that is allowed bythe second motor generator and that is obtained through calculationaccording to the running state (such as the temperature, current, andvoltage) of the second motor generator during braking feedback controlof the vehicle. The feedback limit value of the motor generatorcontroller refers to a braking feedback torque value that is allowed bythe motor generator controller and that is obtained through calculationaccording to the running state (stats of temperature, current, voltage,and the like) of the motor generator controller during braking feedbackcontrol of the vehicle.

Moreover, a braking pedal depth-braking torque curve of the vehicle isobtained according to the ride comfort and the braking performance ofthe vehicle, and a braking pedal depth-braking feedback torque curve ofthe vehicle is obtained according to the braking pedal depth-brakingtorque curve, an economic region of a power system of the vehicle, and apreset braking pedal depth-basic braking torque curve; a current brakingfeedback target value corresponding to the vehicle is obtained accordingto the braking pedal depth-braking feedback torque curve of the vehicle;a minimum feedback value of the vehicle is obtained according to theminimum feedback limit value and the current braking feedback targetvalue; and braking feedback control is performed on the second motorgenerator according to the minimum feedback value or braking feedbackcontrol is performed on the first motor generator and the second motorgenerator.

For the braking feedback control method for a vehicle In someembodiments of the present disclosure, dynamic energy during braking ofthe vehicle can be converted by using a transmission system and a motorinto electric energy to be stored in a power battery, and the electricenergy is then used in traction and driving. Meanwhile, a generatedmotor braking torque exerts a braking effect on the driving wheels byusing the transmission system, so a loss of energy being turned intofriction thermal energy is avoided, thus increasing energy useefficiency of the vehicle. Moreover, through analysis of factors such asthe operation mode (hybrid electric vehicle HEV or pure EV operationmode) of the vehicle, the speed of the vehicle, the slope of a road, theeconomic region of the power system (including the power battery, themotor generator controller, and the motor generator), and the ridecomfort and the steering capability of the vehicle, in combination witha braking torque curve of the vehicle and a basic braking torque curve,and in combination with the state of the braking pedal, the speed of thevehicle, the power system feedback limit, and vehicle status informationsuch as the state of a system related module (such as the ESC), aprocedure of braking feedback control of the vehicle is analyzedcomprehensively.

As shown in FIG. 24, a specific procedure of braking feedback control ofthe vehicle according to an embodiment of the present disclosureincludes:

S201: Determine, by using an input signal, whether a condition to enterbraking feedback control is met, where the meeting the condition toenter braking feedback control is: the speed of the vehicle>Vmin and thedepth of the braking pedal>0 and the ABS is in a non-working state.

S202: Monitor current running states (such as the temperature, current,and voltage) of the first motor generator and the second motorgenerator, calculate a feedback limit value of the first motor generatorand a feedback limit value of the second motor generator.

S203: Monitor a current running state (such as the temperature, current,and voltage) of the motor generator controller ECN, and calculate afeedback limit value of the ECN.

S204: The BMS monitors the state of each single battery in the powerbattery, calculates a current rechargeable power of the power battery,and calculates the current feedback limit value of the power batteryaccording to the current allowable charging power of the power battery.

S205: Compare the three feedback limit values in Steps S202, S203, andS204 to obtain the minimum feedback limit value of the three.

S206: Fit a braking pedal depth-braking torque curve of the vehicleaccording to the ride comfort and braking performance of the vehicle,then fit a braking feedback torque curve corresponding to a brakingpedal depth of the vehicle, a braking pedal depth-braking feedbacktorque curve by comprehensively considering the states such as theeconomic region of the power system (including the power battery, themotor generator controller, and the motor generator) of the vehicle, anda preset braking pedal depth-basic braking torque curve in the vehicle,and use the braking pedal depth-braking feedback torque curve as aninput target value of feedback control, so a current braking feedbacktarget value corresponding to the vehicle may be obtained according tothe depth of the braking pedal.

According to an embodiment of the present disclosure, the braking torqueof basic braking performed on the vehicle may be further obtainedaccording to the depth of the braking pedal and the preset braking pedaldepth-basic braking torque curve.

S207: Compare the two feedback values in Steps S205 and S206 to obtainthe minimum feedback value of the vehicle. That is, the smaller one ofthe minimum feedback limit value and the current braking feedback targetvalue is used as the minimum feedback value of the vehicle. The minimumfeedback value of the vehicle is an actual electric braking torqueduring braking feedback control of the vehicle.

S208: According to the minimum feedback value obtained throughcomparison in S207, drive the first motor generator and the second motorgenerator to perform braking feedback control or drive the second motorgenerator to perform braking feedback control, charge electric energyinto the power battery, and simultaneously provide a frictional force tothe wheel, thus achieving the objective of reducing the speed of thevehicle.

S209: When executing braking feedback control, the ECN sends a targettorque signal of an engine unit to an ECM.

That is, when braking feedback control is performed on the first motorgenerator and the second motor generator or braking feedback control isperformed on the second motor generator, a target torque of the engineunit is sent to the ECM, and the ECM controls the engine unit accordingto the target torque.

S210: When the minimum feedback value is obtained through comparison,the vehicle enters a braking feedback state, and the first motorgenerator and the second motor generator perform braking feedback or thesecond motor generator performs braking feedback.

S211: When the speed of the vehicle is greater than a first speedthreshold value (e.g., 40 Km/h) or the first motor generator executesbraking feedback, control the power switching device, for example, thesynchronizer to engage.

S212: Determine, by using an input signal, whether a condition to exitbraking feedback control is met, and the meeting the condition to exitbraking feedback control is: the speed of the vehicle is less than orequal to Vmin or the depth of the braking pedal is less than or equal to0 or the ABS is in a working state.

During fitting of the vehicle braking feedback torque curve, the ridecomfort of the vehicle, the braking performance of the vehicle, and theeconomic region of the power system are fully considered; moreover, itis considered that when the vehicle is in different running operatingconditions (for example, emergent braking, moderate or mild braking,braking on a long downhill slope), because the distributions of brakingtorques are different during braking of the vehicle, different motorgenerators (the second motor generator is primary, and the first motorgenerator is secondary) performs torque feedback.

According to an embodiment of the present disclosure, if the minimumfeedback value is less than or equal to a maximum output braking torqueof the second motor generator, the second motor generator is controlledto output the minimum feedback value; and if the minimum feedback valueis greater than a maximum output braking torque of the second motorgenerator, the second motor generator and the first motor generator arecontrolled to jointly output the minimum feedback value, where a brakingtorque output by the first motor generator is less than a braking torqueoutput by the second motor generator.

In some embodiments of the present disclosure, during braking feedbackcontrol of the vehicle, the distribution of braking forces and brakingtorques at the front and rear wheels of the vehicle directly affects thestability in the braking direction of the vehicle and the efficiency ofrecycling braking energy. For the braking feedback control method for avehicle In some embodiments of the present disclosure, a motor brakingfeedback torque curve corresponding to the travel of a braking pedal,that is, a braking pedal depth-braking feedback torque curve iscalculated and formulated according to a basic braking pedal travel anda deceleration curve. The travel ζ (for example, ζ=20%) of the brakingpedal is assumed, so a corresponding motor braking torque T may becalculated, so as to further fit a rated curve. Next, proportions ofbraking forces and braking torques at the front and rear wheels aredecided according to the speed of the vehicle, the state of the road,and the braking force requirement. Eventually, the range of aregenerative braking force of the motor is decided according to a torquecharacteristic of the motor, so as to determine proportions and valuesof the regenerative braking force and the frictional braking force.Under the condition of meeting a braking requirement of a driver and thewheels of the vehicle are not locked, energy feedback generated frombraking of the second motor generators should be maximized at thedriving wheels. For a series-parallel energy-efficient four-wheel drivevehicle, distribution proportions of braking forces of the motors of thefront and rear wheels, that is, distribution proportions of the brakingtorques of the first and second motor generators, are formulated tomaximize recycling the braking energy of the vehicle. Because in theseries-parallel energy-efficient four-wheel drive vehicle, the power andtorque of the second motor generator are both greater than those of thefirst motor generator, under the premise of allowing braking feedback,the braking force is mostly allocated on the rear-wheel drive, so thatthe rear wheels bear a greater braking force F (the second motorgenerator is primary, and the first motor generator is secondary). Whenthe requirement for a braking force is low, the second motor generatorprovides a braking force. When the requirement for a braking force ishigh, the second motor generator first provides a braking force, andwhen the braking force of the second motor generator is sufficient, thefirst motor generator then provides an auxiliary braking force. In otherwords, if the first motor generator provides a maximum braking torqueTa, the second motor generator provides a maximum braking torque Tb, andit is determined according to a travel of the braking pedal that themaximum electric braking torque required for the vehicle is Tmax (thatis, the minimum feedback value of the vehicle), the distribution of aregenerative braking force has the following cases:

(1) If T is less than or equal to Tb, the required rear wheel brakingtorque is entirely provided through regenerative braking of the secondmotor generator, and in this case, the rear wheels are in a pure motorregenerative braking mode.

(2) If T is greater than Tb, a large part of the required braking torqueis provided by the second motor generator, and the first motor generatorprovides a small part, that is, the second motor generator and the firstmotor generator jointly generate the braking torque through regenerativebraking.

As shown in FIG. 25, the procedure of distributing an electric brakingtorque during braking feedback control of the vehicle according to anembodiment of the present disclosure includes:

S101: Determine the intention of a driver according to the depth of thebraking pedal, to determine whether to adopt braking feedback control.If not, the process ends directly; or if yes, perform the followingoperations.

S102: Determine an electric braking torque T according to the depth ofthe braking pedal.

S103: Determine, according to the characteristic of a rear motor, thatis, the second motor generator, a maximum braking torque Tb of the rearmotor.

S104: Determine, according to the characteristic of a front motor, thatis, the first motor generator, a maximum braking torque Ta of the frontmotor.

S105: Compare the values in Steps S102, S103, and S104.

S106: Determine the distribution of braking torques according to thecomparison of values in Step S105.

S107: If T is less than or equal to Tb, determine the distribution ofbraking torques, and perform Step S108.

S108: Determine, according to a determining condition that T is lessthan or equal to Tb, that the rear motor provides the entire brakingtorque.

S109: If Tmax is greater than Tb, determine the distribution of brakingtorques, and perform Step S110.

S110: Determine, according to a determining condition that T is greaterthan Tb, that the rear motor provides a large part of the brakingtorque, and the front motor provides a small part of the braking torque.

S111: Determine the distribution of braking torques according to thecomparison above.

S112: After the distribution of braking torques is determined, control acorresponding motor to provide a regenerative braking force.

S113: The vehicle performs braking energy feedback.

It should be noted that regardless of whether both the first motorgenerator and the second motor generator execute regenerative brakingfeedback or only the second motor generator executes regenerativebraking feedback, the vehicle needs to perform basic braking, and thebraking torque of basic braking performed on the vehicle is obtainedaccording to the depth of the braking pedal and the preset braking pedaldepth-basic braking torque curve.

In some embodiments of the present disclosure, during the distributionof braking torques at the front and rear wheels, factors such as theenergy feedback efficiency of braking, the braking safety, and thedriving experience of the vehicle are fully considered, and thedistribution of braking forces at the front and rear wheels from thetravel of the braking pedal during mechanical braking is considered.

Therefore, in conclusion, in the embodiments of the present disclosure,various input information are fully and accurately analyzed andconsidered, and control strategies in various stages are optimized, thebraking feedback control of the vehicle are desirably improved in theaspects of safety, economic efficiency, and steering capability.

For the braking feedback control method for a vehicle according toembodiments of the present disclosure, during braking feedback of thevehicle, a maximum required braking torque of the vehicle is obtainedaccording to the depth of a braking pedal, and a braking torque of afirst motor generator, a braking torque of a second motor generator, anda braking torque of a mechanical friction braking system of the vehicleare properly allocated according to the maximum required braking torque.The energy feedback efficiency, braking safety, and driving comfortduring braking of the vehicle are fully considered, so high fueleconomic efficiency, low discharge, and stable driving performance canbe realized, thus maximizing the mileage, the ride comfort, and thesteering capability of the vehicle. Meanwhile, in some embodiments ofthe present disclosure, power output by the engine unit and/or a firstmotor generator may be output to an output unit via a power switchingdevice, and the output unit then outputs the power to at least one offront and rear wheels of the vehicle. Further, because of the provisionof a second motor generator, the second motor generator may performtorque compensation on at least one of the front and rear wheels, andmay also cooperate with the engine unit and the first motor generator todrive the vehicle, thus increasing the number of operation modes of thevehicle, so that the vehicle may be better adapted to differentoperating conditions, thus achieving better fuel economic efficiencywhile reducing the emission of harmful gases. In addition, the method issimple and reliable and is easy to implement.

In addition, embodiments of the present disclosure further provide avehicle. As shown in FIG. 26, the vehicle includes: an engine unit 1; atransmission unit 2 a, where the transmission unit 2 a is adapted toselectively couple with the engine unit 1 and also configured totransmit the power generated by the engine unit 1; a first motorgenerator 41, where the first motor generator 41 is coupled with thetransmission unit 2 a; an output unit 5, where the output unit 5 isconfigured to transmit the power transmitted by the transmission unit 2a to at least one of front and rear wheels of the vehicle; a powerswitching device (e.g., a synchronizer 6), where the power switchingdevice (e.g., the synchronizer 6) is adapted to enable or interruptpower transmission between the transmission unit 2 a and the output unit5; a second motor generator 42, where the second motor generator 42 isconfigured to drive at least one of the front and rear wheels; a powerbattery 300, where the power battery 300 is respectively connected tothe first motor generator 41 and the second motor generator 42 to supplypower to the first motor generator 41 and the second motor generator 42;a controller 500, where when the current speed of the vehicle is greaterthan a preset speed, the depth of a braking pedal of the vehicle isgreater than 0, and an anti-lock braking system of the vehicle is in anon-working state, the controller controls the vehicle to enter abraking feedback control mode, where when the vehicle is in the brakingfeedback control mode, the controller 500 obtains a required brakingtorque corresponding to the vehicle according to the depth of thebraking pedal, and distributes a braking torque of the first motorgenerator 41, a braking torque of the second motor generator 42, and abraking torque of basic braking performed on the vehicle according tothe required braking torque. In addition, for other components shown inFIG. 26, reference may be made to the description in the embodimentcorresponding to FIG. 8.

The power switching device is configured as a synchronizer 6, and thesynchronizer 6 is adapted to selectively synchronize between the outputunit 5 and the transmission unit 2 a.

According to an embodiment of the present disclosure, when the vehicleis in the braking feedback control mode, the controller 500 obtains afeedback limit value of the first motor generator 41 and a feedbacklimit value of the second motor generator 42 according to currentrunning states of the first motor generator 41 and the second motorgenerator 42, obtains a feedback limit value of a motor generatorcontroller according to a current running state of the motor generatorcontroller of the vehicle, and obtains a current feedback limit value ofthe power battery 300 according to a current allowable charging power ofthe power battery 300, and the controller 500 obtains, according to thefeedback limit value of the first motor generator 41, the feedback limitvalue of the second motor generator 42, the feedback limit value of themotor generator controller, and the current feedback limit value of thepower battery 300, the minimum feedback limit value of the feedbacklimit value of the first motor generator 41, the feedback limit value ofthe second motor generator 42, the feedback limit value of the motorgenerator controller, and the current feedback limit value of the powerbattery 300.

Moreover, the controller 500 further obtains a braking pedaldepth-braking torque curve of the vehicle according to the ride comfortand the braking performance of the vehicle, and obtains a braking pedaldepth-braking feedback torque curve of the vehicle according to thebraking pedal depth-braking torque curve, an economic region of a powersystem of the vehicle, and a preset braking pedal depth-basic brakingtorque curve, and obtains a current braking feedback target valuecorresponding to the vehicle according to the braking pedaldepth-braking feedback torque curve of the vehicle.

According to an embodiment of the present disclosure, the controller 50obtains a minimum feedback value of the vehicle according to the minimumfeedback limit value and the current braking feedback target value, andperforms, according to the minimum feedback value, braking feedbackcontrol on the second motor generator 42 or braking feedback control onthe first motor generator 41 and the second motor generator 42.

When braking feedback control is performed on the first motor generator41 and the second motor generator 42 or braking feedback control isperformed on the second motor generator 42, the controller 500 sends atarget torque of the engine unit 1 to an ECM, and the ECM controls theengine unit 1 according to the target torque.

According to an embodiment of the present disclosure, when the speed ofthe vehicle is greater than a first speed threshold value or the firstmotor generator 41 executes braking feedback, the controller 500controls the synchronizer 6 to engage.

According to an embodiment of the present disclosure, the controller 500further obtains, according to the depth of the braking pedal and thepreset braking pedal depth-basic braking torque curve, the brakingtorque of basic braking performed on the vehicle.

According to an embodiment of the present disclosure, if the minimumfeedback value is less than or equal to the maximum output brakingtorque of the second motor generator 42, the controller 500 controls thesecond motor generator 42 to output the minimum feedback value. If theminimum feedback value is greater than the maximum output braking torqueof the second motor generator 42, the controller 500 controls the secondmotor generator 42 and the first motor generator 41 to jointly outputthe minimum feedback value, where the braking torque output by the firstmotor generator 41 is less than the braking torque output by the secondmotor generator 42.

In another embodiment of the present disclosure, technologies such as anelectronically controlled brake (ECB) system and an electronic brakeforce distribution (EBD) may be further used, so a recycling proportionof braking energy may be increased. Because the ECB may avoidconsidering the provision of braking experience the same as that of afuel vehicle, when a braking pedaling force is small, braking energy maybe recycled, so that a recycling range of the braking energy isenlarged.

For the vehicle according to embodiments of the present disclosure,during braking feedback, a maximum required braking torque can beobtained according to the depth of a braking pedal, and a braking torqueof first motor generator, a braking torque of the second motorgenerator, and a braking torque of a mechanical friction braking systemof the vehicle can be properly distributed according to the maximumrequired braking torque. The energy feedback efficiency, braking safety,and driving comfort during braking of the vehicle are fully considered,so high fuel economic efficiency, low discharge, and stable drivingperformance can be realized, thus maximizing the mileage, the ridecomfort, and the steering capability. Meanwhile, in some embodiments ofthe present disclosure, power output by the engine unit and/or a firstmotor generator may be output to an output unit via a power switchingdevice, and the output unit then outputs the power to at least one offront and rear wheels of the vehicle. Further, because of the provisionof a second motor generator, the second motor generator may performtorque compensation on at least one of the front and rear wheels, andmay also cooperate with the engine unit and the first motor generator todrive the vehicle, thus increasing the number of operation modes of thevehicle, so that the vehicle may be better adapted to differentoperating conditions, thus achieving better fuel economic efficiencywhile reducing the emission of harmful gases.

Any processes or methods described in the flowcharts or in other mannersmay be understood as modules, segments or parts of code including one ormore executable instructions configured to implement steps of specificlogic functions or processes, and the scope of the preferredimplementation manners of the present disclosure includes otherimplementations. The functions may be executed in an order other thanthose shown or discussed. For example, the functions are executedsubstantially at the same time according to the involved functions orthe functions are executed in an opposite order, which should beunderstood by those skilled in the art to which embodiments of thepresent disclosure belong.

The logic and/or steps represented in the flowcharts or described hereinin other manners may be, for example, regarded as a sequenced list ofexecutable instructions for implementing logic functions, and may bespecifically implemented in any computer readable medium for use byinstruction execution systems, devices or equipment (for example, acomputer-based system, a system including a processor or another systemthat may take an instruction from instruction execution systems, devicesor equipment and execute the instruction), or for use in combinationwith these instruction execution systems, devices or equipment. As forthis specification, the “computer readable medium” may be any devicethat may include, store, communicate, propagate or transmit a programfor use by instruction execution systems, devices or equipment or foruse in combination with these instruction execution systems, devices orequipment. A more specific example (a non-exclusive list) of thecomputer readable medium includes the following: an electronicconnection portion (electronic device), a portable computer cassette(magnetic device), a random access memory (RAM), a read-only memory(ROM), an erasable programmable read-only memory (EPROM or flash-drivememory), a fiber device, and a compact disc read-only memory (CDROM)having one or more cables. In addition, the computer readable medium mayeven be paper or another suitable medium on which the program isprinted, because, for example, optical scanning may be performed on thepaper or the another medium, the program is then obtained in anelectronic manner by means of editing, deciphering or processing inanother suitable manner when necessary, and the program is stored in acomputer memory.

It would be appreciated that the parts of the present disclosure may beimplemented by using hardware, software, firmware or a combinationthereof. In the foregoing implementation manner, multiple steps ormethods may be implemented by using software or firmware that is storedin a memory and executed by a suitable instruction execution system. Forexample, during implementation of hardware, as in any anotherimplementation manner, any one or a combination of the followingtechnologies well known in the art may be used for implementation: adiscrete logic circuit having a logic gate circuit configured toimplement a logic function on a data signal, an application-specificintegrated circuit having a suitable combinational logic gate circuit, aprogrammable gate array (PGA), a field-programmable gate array (FPGA),and the like.

Those skilled in the art may understand that implementation of all orsome of the steps carried in the methods in the foregoing embodimentsmay be accomplished by using a program instructing related hardware, andthe program may be stored in a computer readable store medium. When theprogram is run, one or a combination of the steps in the methodembodiments is included.

In addition, various functional units in various embodiments of thepresent disclosure may be integrated in one processing module, orvarious units may exist separately in a physical form, or two or moreunits may be integrated in one module. The foregoing integrated modulemay be implemented in the form of hardware, or may be implemented in theform of a software function module. When the integrated module isimplemented in the form of a software functional module and sold or usedas an independent product, the integrated module may be stored in acomputer-readable storage medium.

The storage medium mentioned in the foregoing may be a read-only memory,a disk, a disc or the like.

Reference throughout this specification to “an embodiment,” “someembodiments,” “an example,” “a specific example,” or “some examples,”means that a particular feature, structure, material, or characteristicdescribed in connection with the embodiment or example is included in atleast one embodiment or example of the present disclosure. Thus, theappearances of the phrases such as “in an embodiment,” “in someembodiments”, “in an example,” “in a specific example,” or “in someexamples,” in various places throughout this specification are notnecessarily referring to the same embodiment or example of the presentdisclosure. Furthermore, the particular features, structures, materials,or characteristics may be combined in any suitable manner in one or moreembodiments or examples.

Although embodiments of the present disclosure have been shown anddescribed, it would be appreciated by those skilled in the art thatvarious changes, modifications, replacements and alternatives can bemade to the embodiments without departing from the principles and spiritof the present disclosure, and the scope of the present disclosure is asdefined by the appended claims and equivalents thereof.

What is claimed is:
 1. A braking feedback control method for a vehicle,wherein the vehicle comprises an engine unit, a transmission unitadapted to selectively couple with the engine unit and configured totransmit the power generated by the engine unit, a first motor generatorcoupled with the transmission unit, an output unit, a power switchingdevice, a second motor generator configured to drive at least one offront and rear wheels of the vehicle, and a power battery for supplyingpower to the first motor generator and the second motor generator,wherein the output unit is configured to transmit the power transmittedby the transmission unit to at least one of the front and rear wheels ofthe vehicle, the power switching device is adapted to enable orinterrupt power transmission between the transmission unit and theoutput unit, and the braking feedback control method comprises thefollowing steps: detecting a current speed of the vehicle and a depth ofa braking pedal of the vehicle; and when the current speed of thevehicle is greater than a preset speed, the depth of the braking pedalis greater than 0, and an anti-lock braking system of the vehicle is ina non-working state, controlling the vehicle to enter a braking feedbackcontrol mode, wherein when the vehicle is in the braking feedbackcontrol mode, a required braking torque corresponding to the vehicle isobtained according to the depth of the braking pedal, and a brakingtorque of the first motor generator, a braking torque of the secondmotor generator, and a braking torque of basic braking performed on thevehicle are distributed according to the required braking torque.
 2. Thebraking feedback control method for a vehicle according to claim 1,wherein the power switching device is configured as a synchronizer, andthe synchronizer is adapted to selectively synchronize between theoutput unit and the transmission unit.
 3. The braking feedback controlmethod for a vehicle according to claim 1, wherein when the vehicle isin the braking feedback control mode, a feedback limit value of thefirst motor generator and a feedback limit value of the second motorgenerator are obtained according to current running states of the firstmotor generator and the second motor generator; a feedback limit valueof the motor generator controller is obtained according to a currentrunning state of a motor generator controller of the vehicle; a currentallowable charging power of the power battery is calculated according toa working state of the power battery, and a current feedback limit valueof the power battery is obtained according to the current allowablecharging power of the power battery; and a minimum feedback limit valueof the feedback limit value of the first motor generator, the feedbacklimit value of the second motor generator, the feedback limit value ofthe motor generator controller, and the current feedback limit value ofthe power battery is obtained.
 4. The braking feedback control methodfor a vehicle according to claim 3, wherein a braking pedaldepth-braking torque curve of the vehicle is obtained according to theride comfort and the braking performance of the vehicle, and a brakingpedal depth-braking feedback torque curve of the vehicle is obtainedaccording to the braking pedal depth-braking torque curve, an economicregion of a power system of the vehicle, and a preset braking pedaldepth-basic braking torque curve; a current braking feedback targetvalue corresponding to the vehicle is obtained according to the brakingpedal depth-braking feedback torque curve of the vehicle; a minimumfeedback value of the vehicle is obtained according to the minimumfeedback limit value and the current braking feedback target value; andaccording to the minimum feedback value, braking feedback control isperformed on the second motor generator or braking feedback control isperformed on the first motor generator and the second motor generator.5. The braking feedback control method for a vehicle according to claim4, wherein when braking feedback control is performed on the first motorgenerator and the second motor generator or braking feedback control isperformed on the second motor generator, a target torque of the engineunit is sent to an engine control module (ECM), and the ECM controls theengine unit according to the target torque.
 6. The braking feedbackcontrol method for a vehicle according to claim 4, wherein when thespeed of the vehicle is greater than a first speed threshold value orthe first motor generator executes braking feedback, the power switchingdevice is controlled to engage.
 7. The braking feedback control methodfor a vehicle according to claim 4, wherein the braking torque of basicbraking performed on the vehicle is obtained according to the depth ofthe braking pedal and the preset braking pedal depth-basic brakingtorque curve.
 8. The braking feedback control method for a vehicleaccording to claim 4, wherein if the minimum feedback value is less thanor equal to a maximum output braking torque of the second motorgenerator, the second motor generator is controlled to output theminimum feedback value; or if the minimum feedback value is greater thana maximum output braking torque of the second motor generator, thesecond motor generator and the first motor generator are controlled tojointly output the minimum feedback value, wherein a braking torqueoutput by the first motor generator is less than a braking torque outputby the second motor generator.
 9. A vehicle, comprising: an engine unit;a transmission unit adapted to selectively couple with the engine unitand also configured to transmit the power generated by the engine unit;a first motor generator coupled with the transmission unit; an outputunit configured to transmit the power transmitted by the transmissionunit to at least one of the front and rear wheels of the vehicle; apower switching device adapted to enable or interrupt power transmissionbetween the transmission unit and the output unit; a second motorgenerator configured to drive at least one of the front and rear wheels;a power battery respectively connected to the first motor generator andthe second motor generator to supply power to the first motor generatorand the second motor generator; and a controller, wherein when a currentspeed of the vehicle is greater than a preset speed, a depth of thebraking pedal of the vehicle is greater than 0, and an anti-lock brakingsystem of the vehicle is in a non-working state, the controller controlsthe vehicle to enter a braking feedback control mode, wherein when thevehicle is in the braking feedback control mode, the controller obtainsa required braking torque corresponding to the vehicle according to thedepth of the braking pedal, and distributes, according to the requiredbraking torque, a braking torque of the first motor generator, a brakingtorque of the second motor generator, and a braking torque of basicbraking performed on the vehicle.
 10. The vehicle according to claim 9,wherein the power switching device is configured as a synchronizer, andthe synchronizer is adapted to selectively synchronize between theoutput unit and the transmission unit.
 11. The vehicle according toclaim 10, wherein when the vehicle is in the braking feedback controlmode, the controller obtains a feedback limit value of the first motorgenerator and a feedback limit value of the second motor generatoraccording to current running states of the first motor generator and thesecond motor generator, obtains a feedback limit value of the motorgenerator controller according to a current running state of a motorgenerator controller of the vehicle, and obtains a current feedbacklimit value of the power battery according to the current allowablecharging power of the power battery, and the controller obtains,according to the feedback limit value of the first motor generator, thefeedback limit value of the second motor generator, the feedback limitvalue of the motor generator controller, and the current feedback limitvalue of the power battery, a minimum feedback limit value of thefeedback limit value of the first motor generator, the feedback limitvalue of the second motor generator, the feedback limit value of themotor generator controller, and the current feedback limit value of thepower battery.
 12. The vehicle according to claim 11, wherein thecontroller further obtains a braking pedal depth-braking torque curve ofthe vehicle according to the ride comfort and the braking performance ofthe vehicle, obtains a braking pedal depth-braking feedback torque curveof the vehicle according to the braking pedal depth-braking torquecurve, an economic region of a power system of the vehicle, and a presetbraking pedal depth-basic braking torque curve, and obtains a currentbraking feedback target value corresponding to the vehicle according tothe braking pedal depth-braking feedback torque curve of the vehicle.13. The vehicle according to claim 12, wherein the controller obtains aminimum feedback value of the vehicle according to the minimum feedbacklimit value and the current braking feedback target value, and performs,according to the minimum feedback value, braking feedback control on thesecond motor generator or braking feedback control on the first motorgenerator and the second motor generator.
 14. The vehicle according toclaim 13, wherein when braking feedback control is performed on thefirst motor generator and the second motor generator or braking feedbackcontrol is performed on the second motor generator, the controller sendsa target torque of the engine unit to an engine control module (ECM),and the ECM controls the engine unit according to the target torque. 15.The vehicle according to claim 13, wherein when the speed of the vehicleis greater than a first speed threshold value or the first motorgenerator executes braking feedback, the controller controls thesynchronizer to engage.
 16. The vehicle according to claim 12, whereinthe controller further obtains the braking torque of basic brakingperformed on the vehicle according to the depth of the braking pedal andthe preset braking pedal depth-basic braking torque curve.
 17. Thevehicle according to claim 13, wherein if the minimum feedback value isless than or equal to a maximum output braking torque of the secondmotor generator, the controller controls the second motor generator tooutput the minimum feedback value; and if the minimum feedback value isgreater than a maximum output braking torque of the second motorgenerator, the controller controls the second motor generator and thefirst motor generator to jointly output the minimum feedback value,wherein a braking torque output by the first motor generator is lessthan a braking torque output by the second motor generator.
 18. Abraking feedback control method for a vehicle, wherein the vehiclecomprises an engine unit, a transmission unit adapted to selectivelycouple with the engine unit and configured to transmit the powergenerated by the engine unit, a first motor generator coupled with thetransmission unit, and a second motor generator configured to drive atleast one of front and rear wheels of the vehicle, and a power batteryfor supplying power to the first motor generator and the second motorgenerator, the method comprising: controlling the vehicle to enter abraking feedback control mode, in which, a required braking torquecorresponding to the vehicle is obtained according to a depth of thebraking pedal, and a braking torque of the first motor generator, abraking torque of the second motor generator, and a braking torque ofbasic braking performed on the vehicle are distributed according to therequired braking torque.